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    SubjectRe: [PATCH 1/3] ARM: iommu: tegra/common: Initial support for IOVMM driver
    I'm not very knowledgeable about IOMMUs in general, so my comments are more
    about general style.

    * hdoyu@nvidia.com wrote:
    > From: Hiroshi DOYU <hdoyu@nvidia.com>
    >
    > This is the tegra specific IOMMU framework, independent of H/W. H/W

    You should keep the spelling of "Tegra" consistent.

    > dependent modules are to be registered to this framework so that this
    > can support different IOMMU H/Ws among Tegra generations, Tegra2/GART,
    > and Tegra3/SMMU H/Ws.
    >
    > Most of this part could be replaced with a generic IOMMU
    > framework. This is expected to ease finding similarities with
    > different platforms, with the intention of solving problems once in a
    > generic framework which everyone can use.
    >
    > Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
    > Cc: Hiro Sugawara <hsugawara@nvidia.com>
    > Cc: Krishna Reddy <vdumpa@nvidia.com>
    > ---
    > arch/arm/mach-tegra/include/mach/iovmm.h | 283 +++++++++
    > drivers/iommu/Kconfig | 6 +
    > drivers/iommu/Makefile | 1 +
    > drivers/iommu/tegra-iovmm.c | 936 ++++++++++++++++++++++++++++++
    > 4 files changed, 1226 insertions(+), 0 deletions(-)
    > create mode 100644 arch/arm/mach-tegra/include/mach/iovmm.h
    > create mode 100644 drivers/iommu/tegra-iovmm.c
    >
    > diff --git a/arch/arm/mach-tegra/include/mach/iovmm.h b/arch/arm/mach-tegra/include/mach/iovmm.h
    > new file mode 100644
    > index 0000000..6fd0bb6
    > --- /dev/null
    > +++ b/arch/arm/mach-tegra/include/mach/iovmm.h
    > @@ -0,0 +1,283 @@
    > +/*
    > + * Copyright (c) 2010-2011, NVIDIA Corporation.
    > + *
    > + * This program is free software; you can redistribute it and/or modify
    > + * it under the terms of the GNU General Public License as published by
    > + * the Free Software Foundation; either version 2 of the License, or
    > + * (at your option) any later version.
    > + *
    > + * This program is distributed i the hope that it will be useful, but WITHOUT
    > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    > + * more details.
    > + *
    > + * You should have received a copy of the GNU General Public License along
    > + * with this program; if not, write to the Free Software Foundation, Inc.,
    > + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
    > + */
    > +
    > +#include <linux/list.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/miscdevice.h>
    > +#include <linux/rbtree.h>
    > +#include <linux/rwsem.h>
    > +#include <linux/spinlock.h>
    > +#include <linux/types.h>
    > +
    > +#ifndef _MACH_TEGRA_IOVMM_H_
    > +#define _MACH_TEGRA_IOVMM_H_
    > +
    > +typedef u32 tegra_iovmm_addr_t;
    > +
    > +struct tegra_iovmm_device_ops;
    > +
    > +/* each I/O virtual memory manager unit should register a device with
    > + * the iovmm system
    > + */

    Generally, multi-line comments have the starting /* and ending */ on separate
    lines. Also since this API is public it may be better to document it using
    kerneldoc.

    > +struct tegra_iovmm_device {
    > + struct tegra_iovmm_device_ops *ops;
    > + const char *name;
    > + struct list_head list;
    > + int pgsize_bits;
    > +};
    > +
    > +/* tegra_iovmm_domain serves a purpose analagous to mm_struct as defined in
    > + * <linux/mm_types.h> - it defines a virtual address space within which
    > + * tegra_iovmm_areas can be created.
    > + */
    > +struct tegra_iovmm_domain {
    > + atomic_t clients;
    > + atomic_t locks;
    > + spinlock_t block_lock;
    > + unsigned long flags;
    > + wait_queue_head_t delay_lock; /* when lock_client fails */
    > + struct rw_semaphore map_lock;
    > + struct rb_root all_blocks; /* ordered by address */
    > + struct rb_root free_blocks; /* ordered by size */
    > + struct tegra_iovmm_device *dev;
    > +};
    > +
    > +/* tegra_iovmm_client is analagous to an individual task in the task group
    > + * which owns an mm_struct.
    > + */
    > +
    > +struct iovmm_share_group;
    > +
    > +struct tegra_iovmm_client {
    > + const char *name;
    > + unsigned long flags;
    > + struct iovmm_share_group *group;
    > + struct tegra_iovmm_domain *domain;
    > + struct miscdevice *misc_dev;
    > + struct list_head list;
    > +};
    > +
    > +/* tegra_iovmm_area serves a purpose analagous to vm_area_struct as defined
    > + * in <linux/mm_types.h> - it defines a virtual memory area which can be
    > + * mapped to physical memory by a client-provided mapping function. */
    > +
    > +struct tegra_iovmm_area {
    > + struct tegra_iovmm_domain *domain;
    > + tegra_iovmm_addr_t iovm_start;
    > + size_t iovm_length;
    > + pgprot_t pgprot;
    > + struct tegra_iovmm_area_ops *ops;
    > +};
    > +
    > +struct tegra_iovmm_device_ops {
    > + /* maps a VMA using the page residency functions provided by the VMA */
    > + int (*map)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_area *io_vma);
    > + /* marks all PTEs in a VMA as invalid; decommits the virtual addres
    > + * space (potentially freeing PDEs when decommit is true.) */
    > + void (*unmap)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_area *io_vma, bool decommit);
    > + void (*map_pfn)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_area *io_vma,
    > + tegra_iovmm_addr_t offs, unsigned long pfn);
    > + /* ensures that a domain is resident in the hardware's mapping region
    > + * so that it may be used by a client */
    > + int (*lock_domain)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_client *client);
    > + void (*unlock_domain)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_client *client);
    > + /* allocates a vmm_domain for the specified client; may return the same
    > + * domain for multiple clients */
    > + struct tegra_iovmm_domain* (*alloc_domain)(
    > + struct tegra_iovmm_device *dev,
    > + struct tegra_iovmm_client *client);
    > + void (*free_domain)(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_client *client);
    > + int (*suspend)(struct tegra_iovmm_device *dev);
    > + void (*resume)(struct tegra_iovmm_device *dev);
    > +};
    > +
    > +struct tegra_iovmm_area_ops {
    > + /* ensures that the page of data starting at the specified offset
    > + * from the start of the iovma is resident and pinned for use by
    > + * DMA, returns the system pfn, or an invalid pfn if the
    > + * operation fails. */
    > + unsigned long (*lock_makeresident)(struct tegra_iovmm_area *area,
    > + tegra_iovmm_addr_t offs);
    > + /* called when the page is unmapped from the I/O VMA */
    > + void (*release)(struct tegra_iovmm_area *area, tegra_iovmm_addr_t offs);
    > +};
    > +
    > +#ifdef CONFIG_TEGRA_IOVMM
    > +/* called by clients to allocate an I/O VMM client mapping context which
    > + * will be shared by all clients in the same share_group */
    > +struct tegra_iovmm_client *tegra_iovmm_alloc_client(const char *name,
    > + const char *share_group, struct miscdevice *misc_dev);
    > +
    > +size_t tegra_iovmm_get_vm_size(struct tegra_iovmm_client *client);
    > +
    > +void tegra_iovmm_free_client(struct tegra_iovmm_client *client);
    > +
    > +/* called by clients to ensure that their mapping context is resident
    > + * before performing any DMA operations addressing I/O VMM regions.
    > + * client_lock may return -EINTR. */
    > +int tegra_iovmm_client_lock(struct tegra_iovmm_client *client);
    > +int tegra_iovmm_client_trylock(struct tegra_iovmm_client *client);
    > +
    > +/* called by clients after DMA operations are complete */
    > +void tegra_iovmm_client_unlock(struct tegra_iovmm_client *client);
    > +
    > +/* called by clients to allocate a new iovmm_area and reserve I/O virtual
    > + * address space for it. if ops is NULL, clients should subsequently call
    > + * tegra_iovmm_vm_map_pages and/or tegra_iovmm_vm_insert_pfn to explicitly
    > + * map the I/O virtual address to an OS-allocated page or physical address,
    > + * respectively. VM operations may be called before this call returns */
    > +struct tegra_iovmm_area *tegra_iovmm_create_vm(
    > + struct tegra_iovmm_client *client, struct tegra_iovmm_area_ops *ops,
    > + size_t size, size_t align, pgprot_t pgprot, unsigned long iovm_start);
    > +
    > +/* called by clients to "zap" an iovmm_area, and replace all mappings
    > + * in it with invalid ones, without freeing the virtual address range */
    > +void tegra_iovmm_zap_vm(struct tegra_iovmm_area *vm);
    > +
    > +/* after zapping a demand-loaded iovmm_area, the client should unzap it
    > + * to allow the VMM device to remap the page range. */
    > +void tegra_iovmm_unzap_vm(struct tegra_iovmm_area *vm);
    > +
    > +/* called by clients to return an iovmm_area to the free pool for the domain */
    > +void tegra_iovmm_free_vm(struct tegra_iovmm_area *vm);
    > +
    > +/* returns size of largest free iovm block */
    > +size_t tegra_iovmm_get_max_free(struct tegra_iovmm_client *client);
    > +
    > +/* called by client software to map the page-aligned I/O address vaddr to
    > + * a specific physical address pfn. I/O VMA should have been created with
    > + * a NULL tegra_iovmm_area_ops structure. */
    > +void tegra_iovmm_vm_insert_pfn(struct tegra_iovmm_area *area,
    > + tegra_iovmm_addr_t vaddr, unsigned long pfn);
    > +
    > +/* called by clients to return the iovmm_area containing addr, or NULL if
    > + * addr has not been allocated. caller should call tegra_iovmm_put_area when
    > + * finished using the returned pointer */
    > +struct tegra_iovmm_area *tegra_iovmm_find_area_get(
    > + struct tegra_iovmm_client *client, tegra_iovmm_addr_t addr);

    The comment mentions tegra_iovmm_put_area() but the function declared below
    is called tegra_iovmm_area_put().

    > +
    > +struct tegra_iovmm_area *tegra_iovmm_area_get(struct tegra_iovmm_area *vm);
    > +void tegra_iovmm_area_put(struct tegra_iovmm_area *vm);
    > +
    > +/* called by drivers to initialize a tegra_iovmm_domain structure */
    > +int tegra_iovmm_domain_init(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_device *dev, tegra_iovmm_addr_t start,
    > + tegra_iovmm_addr_t end);
    > +
    > +/* called by drivers to register an I/O VMM device with the system */
    > +int tegra_iovmm_register(struct tegra_iovmm_device *dev);
    > +
    > +/* called by drivers to remove an I/O VMM device from the system */
    > +int tegra_iovmm_unregister(struct tegra_iovmm_device *dev);
    > +
    > +#else /* CONFIG_TEGRA_IOVMM */
    > +
    > +static inline struct tegra_iovmm_client *tegra_iovmm_alloc_client(
    > + const char *name, const char *share_group, struct miscdevice *misc_dev)
    > +{
    > + return NULL;
    > +}
    > +
    > +static inline size_t tegra_iovmm_get_vm_size(struct tegra_iovmm_client *client)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline void tegra_iovmm_free_client(struct tegra_iovmm_client *client)
    > +{}

    For readability, the braces should probably go on separate lines.

    > +
    > +static inline int tegra_iovmm_client_lock(struct tegra_iovmm_client *client)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline int tegra_iovmm_client_trylock(struct tegra_iovmm_client *client)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline void tegra_iovmm_client_unlock(struct tegra_iovmm_client *client)
    > +{}
    > +

    Here as well.

    > +static inline struct tegra_iovmm_area *tegra_iovmm_create_vm(
    > + struct tegra_iovmm_client *client, struct tegra_iovmm_area_ops *ops,
    > + size_t size, size_t align, pgprot_t pgprot, unsigned long iovm_start)
    > +{
    > + return NULL;
    > +}
    > +
    > +static inline void tegra_iovmm_zap_vm(struct tegra_iovmm_area *vm) { }
    > +
    > +static inline void tegra_iovmm_unzap_vm(struct tegra_iovmm_area *vm) { }
    > +
    > +static inline void tegra_iovmm_free_vm(struct tegra_iovmm_area *vm) { }

    And here.

    > +static inline size_t tegra_iovmm_get_max_free(struct tegra_iovmm_client *client)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline void tegra_iovmm_vm_insert_pfn(struct tegra_iovmm_area *area,
    > + tegra_iovmm_addr_t vaddr, unsigned long pfn) { }
    > +

    Here.

    > +static inline struct tegra_iovmm_area *tegra_iovmm_find_area_get(
    > + struct tegra_iovmm_client *client, tegra_iovmm_addr_t addr)
    > +{
    > + return NULL;
    > +}
    > +
    > +static inline struct tegra_iovmm_area *tegra_iovmm_area_get(
    > + struct tegra_iovmm_area *vm)
    > +{
    > + return NULL;
    > +}
    > +
    > +static inline void tegra_iovmm_area_put(struct tegra_iovmm_area *vm) { }
    > +

    Here.

    > +static inline int tegra_iovmm_domain_init(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_device *dev, tegra_iovmm_addr_t start,
    > + tegra_iovmm_addr_t end)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline int tegra_iovmm_register(struct tegra_iovmm_device *dev)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline int tegra_iovmm_unregister(struct tegra_iovmm_device *dev)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline int tegra_iovmm_suspend(void)
    > +{
    > + return 0;
    > +}
    > +
    > +static inline void tegra_iovmm_resume(void) { }
    > +#endif /* CONFIG_TEGRA_IOVMM */

    And here. Preferably with a blank line between the closing } and the #endif.

    > +
    > +

    One of these is gratuitous.

    > +#endif
    > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
    > index 5414253..487d1ee 100644
    > --- a/drivers/iommu/Kconfig
    > +++ b/drivers/iommu/Kconfig
    > @@ -131,4 +131,10 @@ config OMAP_IOMMU_DEBUG
    >
    > Say N unless you know you need this.
    >
    > +

    This one also.

    > +# Tegra IOMMU support
    > +
    > +config TEGRA_IOVMM
    > + bool
    > +
    > endif # IOMMU_SUPPORT
    > diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
    > index 2f44487..365eefb 100644
    > --- a/drivers/iommu/Makefile
    > +++ b/drivers/iommu/Makefile
    > @@ -7,3 +7,4 @@ obj-$(CONFIG_IRQ_REMAP) += intr_remapping.o
    > obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
    > obj-$(CONFIG_OMAP_IOVMM) += omap-iovmm.o
    > obj-$(CONFIG_OMAP_IOMMU_DEBUG) += omap-iommu-debug.o
    > +obj-$(CONFIG_TEGRA_IOVMM) += tegra-iovmm.o
    > diff --git a/drivers/iommu/tegra-iovmm.c b/drivers/iommu/tegra-iovmm.c
    > new file mode 100644
    > index 0000000..0f2d996
    > --- /dev/null
    > +++ b/drivers/iommu/tegra-iovmm.c
    > @@ -0,0 +1,936 @@
    > +/*
    > + * Tegra I/O VM manager
    > + *
    > + * Copyright (c) 2010-2011, NVIDIA Corporation.
    > + *
    > + * This program is free software; you can redistribute it and/or modify
    > + * it under the terms of the GNU General Public License as published by
    > + * the Free Software Foundation; either version 2 of the License, or
    > + * (at your option) any later version.
    > + *
    > + * This program is distributed in the hope that it will be useful, but WITHOUT
    > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    > + * more details.
    > + *
    > + * You should have received a copy of the GNU General Public License along
    > + * with this program; if not, write to the Free Software Foundation, Inc.,
    > + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
    > + */
    > +
    > +#include <linux/kernel.h>
    > +#include <linux/spinlock.h>
    > +#include <linux/proc_fs.h>
    > +#include <linux/sched.h>
    > +#include <linux/string.h>
    > +#include <linux/slab.h>
    > +#include <linux/syscore_ops.h>
    > +
    > +#include <mach/iovmm.h>
    > +
    > +/*
    > + * after the best-fit block is located, the remaining pages not needed
    > + * for the allocation will be split into a new free block if the
    > + * number of remaining pages is >= MIN_SPLIT_PAGE.
    > + */
    > +#define MIN_SPLIT_PAGE 4
    > +#define MIN_SPLIT_BYTES(_d) (MIN_SPLIT_PAGE << (_d)->dev->pgsize_bits)
    > +#define NO_SPLIT(m) ((m) < MIN_SPLIT_BYTES(domain))
    > +#define DO_SPLIT(m) ((m) >= MIN_SPLIT_BYTES(domain))
    > +
    > +#define iovmm_start(_b) ((_b)->vm_area.iovm_start)
    > +#define iovmm_length(_b) ((_b)->vm_area.iovm_length)
    > +#define iovmm_end(_b) (iovmm_start(_b) + iovmm_length(_b))
    > +
    > +/* flags for the block */
    > +#define BK_free 0 /* indicates free mappings */
    > +#define BK_map_dirty 1 /* used by demand-loaded mappings */
    > +
    > +/* flags for the client */
    > +#define CL_locked 0
    > +
    > +/* flags for the domain */
    > +#define DM_map_dirty 0
    These flags should be all uppercase.

    > +
    > +struct tegra_iovmm_block {
    > + struct tegra_iovmm_area vm_area;
    > + tegra_iovmm_addr_t start;
    > + size_t length;
    > + atomic_t ref;
    > + unsigned long flags;
    > + unsigned long poison;
    > + struct rb_node free_node;
    > + struct rb_node all_node;
    > +};
    > +
    > +struct iovmm_share_group {
    > + const char *name;
    > + struct tegra_iovmm_domain *domain;
    > + struct list_head client_list;
    > + struct list_head group_list;
    > + spinlock_t lock; /* for client_list */
    > +};
    > +
    > +static LIST_HEAD(iovmm_devices);
    > +static LIST_HEAD(iovmm_groups);
    > +static DEFINE_MUTEX(iovmm_group_list_lock);
    > +static struct kmem_cache *iovmm_cache;
    > +
    > +#define SIMALIGN(b, a) (((b)->start % (a)) ? ((a) - ((b)->start % (a))) : 0)
    > +
    > +size_t tegra_iovmm_get_max_free(struct tegra_iovmm_client *client)
    > +{
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b;
    > + struct tegra_iovmm_domain *domain = client->domain;
    > + tegra_iovmm_addr_t max_free = 0;
    > +
    > + spin_lock(&domain->block_lock);
    > + n = rb_first(&domain->all_blocks);
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, all_node);
    > + n = rb_next(n);
    > + if (test_bit(BK_free, &b->flags)) {
    > + max_free = max_t(tegra_iovmm_addr_t,
    > + max_free, iovmm_length(b));
    > + }
    > + }
    > + spin_unlock(&domain->block_lock);
    > + return max_free;
    > +}
    > +
    > +
    > +static void tegra_iovmm_block_stats(struct tegra_iovmm_domain *domain,
    > + unsigned int *num_blocks, unsigned int *num_free,
    > + tegra_iovmm_addr_t *total, size_t *total_free, size_t *max_free)
    > +{
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b;
    > +
    > + *num_blocks = 0;
    > + *num_free = 0;
    > + *total = 0;
    > + *total_free = 0;
    > + *max_free = 0;
    > +
    > + spin_lock(&domain->block_lock);
    > + n = rb_first(&domain->all_blocks);
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, all_node);
    > + n = rb_next(n);
    > + (*num_blocks)++;
    > + *total += b->length;
    > + if (test_bit(BK_free, &b->flags)) {
    > + (*num_free)++;
    > + *total_free += b->length;
    > + *max_free = max_t(size_t, *max_free, b->length);
    > + }
    > + }
    > + spin_unlock(&domain->block_lock);
    > +}
    > +
    > +static int tegra_iovmm_read_proc(char *page, char **start, off_t off,
    > + int count, int *eof, void *data)
    > +{
    > + struct iovmm_share_group *grp;
    > + size_t max_free, total_free, total;
    > + unsigned int num, num_free;
    > +
    > + int len = 0;
    > +
    > + mutex_lock(&iovmm_group_list_lock);
    > + len += snprintf(page + len, count - len, "\ngroups\n");
    > + if (list_empty(&iovmm_groups))
    > + len += snprintf(page + len, count - len, "\t<empty>\n");
    > + else {
    > + list_for_each_entry(grp, &iovmm_groups, group_list) {
    > + len += snprintf(page + len, count - len,
    > + "\t%s (device: %s)\n",
    > + (grp->name) ? grp->name : "<unnamed>",
    > + grp->domain->dev->name);
    > + tegra_iovmm_block_stats(grp->domain, &num,
    > + &num_free, &total, &total_free, &max_free);
    > + total >>= 10;
    > + total_free >>= 10;
    > + max_free >>= 10;
    > + len += snprintf(page + len, count - len,
    > + "\t\tsize: %uKiB free: %uKiB "
    > + "largest: %uKiB (%u free / %u total blocks)\n",
    > + total, total_free, max_free, num_free, num);
    > + }
    > + }
    > + mutex_unlock(&iovmm_group_list_lock);
    > +
    > + *eof = 1;
    > + return len;
    > +}
    > +
    > +static void iovmm_block_put(struct tegra_iovmm_block *b)
    > +{
    > + BUG_ON(b->poison);
    > + BUG_ON(atomic_read(&b->ref) == 0);
    > + if (!atomic_dec_return(&b->ref)) {
    > + b->poison = 0xa5a5a5a5;
    > + kmem_cache_free(iovmm_cache, b);
    > + }
    > +}
    > +
    > +static void iovmm_free_block(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_block *block)
    > +{
    > + struct tegra_iovmm_block *pred = NULL; /* address-order predecessor */
    > + struct tegra_iovmm_block *succ = NULL; /* address-order successor */
    > + struct rb_node **p;
    > + struct rb_node *parent = NULL, *temp;
    > + int pred_free = 0, succ_free = 0;
    > +
    > + iovmm_block_put(block);
    > +
    > + spin_lock(&domain->block_lock);
    > + temp = rb_prev(&block->all_node);
    > + if (temp)
    > + pred = rb_entry(temp, struct tegra_iovmm_block, all_node);
    > + temp = rb_next(&block->all_node);
    > + if (temp)
    > + succ = rb_entry(temp, struct tegra_iovmm_block, all_node);
    > +
    > + if (pred)
    > + pred_free = test_bit(BK_free, &pred->flags);
    > + if (succ)
    > + succ_free = test_bit(BK_free, &succ->flags);
    > +
    > + if (pred_free && succ_free) {
    > + pred->length += block->length;
    > + pred->length += succ->length;
    > + rb_erase(&block->all_node, &domain->all_blocks);
    > + rb_erase(&succ->all_node, &domain->all_blocks);
    > + rb_erase(&succ->free_node, &domain->free_blocks);
    > + rb_erase(&pred->free_node, &domain->free_blocks);
    > + iovmm_block_put(block);
    > + iovmm_block_put(succ);
    > + block = pred;
    > + } else if (pred_free) {
    > + pred->length += block->length;
    > + rb_erase(&block->all_node, &domain->all_blocks);
    > + rb_erase(&pred->free_node, &domain->free_blocks);
    > + iovmm_block_put(block);
    > + block = pred;
    > + } else if (succ_free) {
    > + block->length += succ->length;
    > + rb_erase(&succ->all_node, &domain->all_blocks);
    > + rb_erase(&succ->free_node, &domain->free_blocks);
    > + iovmm_block_put(succ);
    > + }
    > +
    > + p = &domain->free_blocks.rb_node;
    > + while (*p) {
    > + struct tegra_iovmm_block *b;
    > + parent = *p;
    > + b = rb_entry(parent, struct tegra_iovmm_block, free_node);
    > + if (block->length >= b->length)
    > + p = &parent->rb_right;
    > + else
    > + p = &parent->rb_left;
    > + }
    > + rb_link_node(&block->free_node, parent, p);
    > + rb_insert_color(&block->free_node, &domain->free_blocks);
    > + set_bit(BK_free, &block->flags);
    > + spin_unlock(&domain->block_lock);
    > +}
    > +
    > +/* if the best-fit block is larger than the requested size, a remainder
    > + * block will be created and inserted into the free list in its place.
    > + * since all free blocks are stored in two trees the new block needs to be
    > + * linked into both. */
    > +static struct tegra_iovmm_block *iovmm_split_free_block(
    > + struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_block *block, unsigned long size)
    > +{
    > + struct rb_node **p;
    > + struct rb_node *parent = NULL;
    > + struct tegra_iovmm_block *rem;
    > + struct tegra_iovmm_block *b;
    > +
    > + rem = kmem_cache_zalloc(iovmm_cache, GFP_KERNEL);
    > + if (!rem)
    > + return NULL;
    > +
    > + spin_lock(&domain->block_lock);
    > + p = &domain->free_blocks.rb_node;
    > +
    > + rem->start = block->start + size;
    > + rem->length = block->length - size;
    > + atomic_set(&rem->ref, 1);
    > + block->length = size;
    > +
    > + while (*p) {
    > + parent = *p;
    > + b = rb_entry(parent, struct tegra_iovmm_block, free_node);
    > + if (rem->length >= b->length)
    > + p = &parent->rb_right;
    > + else
    > + p = &parent->rb_left;
    > + }
    > + set_bit(BK_free, &rem->flags);
    > + rb_link_node(&rem->free_node, parent, p);
    > + rb_insert_color(&rem->free_node, &domain->free_blocks);
    > +
    > + p = &domain->all_blocks.rb_node;
    > + parent = NULL;
    > + while (*p) {
    > + parent = *p;
    > + b = rb_entry(parent, struct tegra_iovmm_block, all_node);
    > + if (rem->start >= b->start)
    > + p = &parent->rb_right;
    > + else
    > + p = &parent->rb_left;
    > + }
    > + rb_link_node(&rem->all_node, parent, p);
    > + rb_insert_color(&rem->all_node, &domain->all_blocks);
    > +
    > + return rem;
    > +}
    > +
    > +static int iovmm_block_splitting;

    Could this be moved into the tegra_iovmm_domain structure?

    > +static struct tegra_iovmm_block *iovmm_alloc_block(
    > + struct tegra_iovmm_domain *domain, size_t size, size_t align)
    > +{
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b, *best;
    > + size_t simalign;
    > + unsigned long page_size = 1 << domain->dev->pgsize_bits;
    > +
    > + BUG_ON(!size);
    > +
    > + size = round_up(size, page_size);
    > + align = round_up(align, page_size);
    > + for (;;) {
    > + spin_lock(&domain->block_lock);
    > + if (!iovmm_block_splitting)
    > + break;
    > + spin_unlock(&domain->block_lock);
    > + schedule();
    > + }
    > + n = domain->free_blocks.rb_node;
    > + best = NULL;
    > + while (n) {
    > + tegra_iovmm_addr_t aligned_start, block_ceil;
    > +
    > + b = rb_entry(n, struct tegra_iovmm_block, free_node);
    > + simalign = SIMALIGN(b, align);
    > + aligned_start = b->start + simalign;
    > + block_ceil = b->start + b->length;
    > +
    > + if (block_ceil >= aligned_start + size) {
    > + /* Block has enough size */
    > + best = b;
    > + if (NO_SPLIT(simalign) &&
    > + NO_SPLIT(block_ceil - (aligned_start + size)))
    > + break;
    > + n = n->rb_left;
    > + } else {
    > + n = n->rb_right;
    > + }
    > + }
    > + if (!best) {
    > + spin_unlock(&domain->block_lock);
    > + return NULL;
    > + }
    > +
    > + simalign = SIMALIGN(best, align);
    > + if (DO_SPLIT(simalign)) {
    > + iovmm_block_splitting = 1;
    > + spin_unlock(&domain->block_lock);
    > +
    > + /* Split off misalignment */
    > + b = best;
    > + best = iovmm_split_free_block(domain, b, simalign);
    > + if (best)
    > + simalign = 0;
    > + else
    > + best = b;
    > + }
    > +
    > + /* Unfree designed block */
    > + rb_erase(&best->free_node, &domain->free_blocks);
    > + clear_bit(BK_free, &best->flags);
    > + atomic_inc(&best->ref);
    > +
    > + iovmm_start(best) = best->start + simalign;
    > + iovmm_length(best) = size;
    > +
    > + if (DO_SPLIT((best->start + best->length) - iovmm_end(best))) {
    > + iovmm_block_splitting = 1;
    > + spin_unlock(&domain->block_lock);
    > +
    > + /* Split off excess */
    > + (void)iovmm_split_free_block(domain, best, size + simalign);
    > + }
    > +
    > + iovmm_block_splitting = 0;
    > + spin_unlock(&domain->block_lock);
    > +
    > + return best;
    > +}
    > +
    > +static struct tegra_iovmm_block *iovmm_allocate_vm(
    > + struct tegra_iovmm_domain *domain, size_t size,
    > + size_t align, unsigned long iovm_start)
    > +{
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b, *best;
    > + unsigned long page_size = 1 << domain->dev->pgsize_bits;
    > +
    > + BUG_ON(iovm_start % align);
    > + BUG_ON(!size);
    > +
    > + size = round_up(size, page_size);
    > + for (;;) {
    > + spin_lock(&domain->block_lock);
    > + if (!iovmm_block_splitting)
    > + break;
    > + spin_unlock(&domain->block_lock);
    > + schedule();
    > + }
    > +
    > + n = rb_first(&domain->free_blocks);
    > + best = NULL;
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, free_node);
    > + if ((b->start <= iovm_start) &&
    > + (b->start + b->length) >= (iovm_start + size)) {
    > + best = b;
    > + break;
    > + }
    > + n = rb_next(n);
    > + }
    > +
    > + if (!best)
    > + goto fail;
    > +
    > + /* split the mem before iovm_start. */
    > + if (DO_SPLIT(iovm_start - best->start)) {
    > + iovmm_block_splitting = 1;
    > + spin_unlock(&domain->block_lock);
    > + best = iovmm_split_free_block(domain, best,
    > + (iovm_start - best->start));
    > + }
    > + if (!best)
    > + goto fail;
    > +
    > + /* remove the desired block from free list. */
    > + rb_erase(&best->free_node, &domain->free_blocks);
    > + clear_bit(BK_free, &best->flags);
    > + atomic_inc(&best->ref);
    > +
    > + iovmm_start(best) = iovm_start;
    > + iovmm_length(best) = size;
    > +
    > + BUG_ON(best->start > iovmm_start(best));
    > + BUG_ON((best->start + best->length) < iovmm_end(best));
    > + /* split the mem after iovm_start+size. */
    > + if (DO_SPLIT(best->start + best->length - iovmm_end(best))) {
    > + iovmm_block_splitting = 1;
    > + spin_unlock(&domain->block_lock);
    > + (void)iovmm_split_free_block(domain, best,
    > + (iovmm_start(best) - best->start + size));
    > + }
    > +fail:
    > + iovmm_block_splitting = 0;
    > + spin_unlock(&domain->block_lock);
    > + return best;
    > +}
    > +
    > +int tegra_iovmm_domain_init(struct tegra_iovmm_domain *domain,
    > + struct tegra_iovmm_device *dev, tegra_iovmm_addr_t start,
    > + tegra_iovmm_addr_t end)
    > +{
    > + struct tegra_iovmm_block *b;
    > + unsigned long page_size = 1 << dev->pgsize_bits;
    > +
    > + b = kmem_cache_zalloc(iovmm_cache, GFP_KERNEL);
    > + if (!b)
    > + return -ENOMEM;
    > +
    > + domain->dev = dev;
    > +
    > + atomic_set(&domain->clients, 0);
    > + atomic_set(&domain->locks, 0);
    > + atomic_set(&b->ref, 1);
    > + spin_lock_init(&domain->block_lock);
    > + init_rwsem(&domain->map_lock);
    > + init_waitqueue_head(&domain->delay_lock);
    > +
    > + b->start = round_up(start, page_size);
    > + b->length = round_down(end, page_size) - b->start;
    > +
    > + set_bit(BK_free, &b->flags);
    > + rb_link_node(&b->free_node, NULL, &domain->free_blocks.rb_node);
    > + rb_insert_color(&b->free_node, &domain->free_blocks);
    > + rb_link_node(&b->all_node, NULL, &domain->all_blocks.rb_node);
    > + rb_insert_color(&b->all_node, &domain->all_blocks);
    > +
    > + return 0;
    > +}
    > +
    > +/* If iovm_start != 0, tries to allocate specified iova block if it is free.
    > + * if it is not free, it fails.
    > + */
    > +struct tegra_iovmm_area *tegra_iovmm_create_vm(
    > + struct tegra_iovmm_client *client, struct tegra_iovmm_area_ops *ops,
    > + size_t size, size_t align, pgprot_t pgprot, unsigned long iovm_start)
    > +{
    > + struct tegra_iovmm_block *b;
    > + struct tegra_iovmm_domain *domain;
    > +
    > + if (!client)
    > + return NULL;
    > +
    > + domain = client->domain;
    > +
    > + if (iovm_start)
    > + b = iovmm_allocate_vm(domain, size, align, iovm_start);
    > + else
    > + b = iovmm_alloc_block(domain, size, align);
    > + if (!b)
    > + return NULL;
    > +
    > + b->vm_area.domain = domain;
    > + b->vm_area.pgprot = pgprot;
    > + b->vm_area.ops = ops;
    > +
    > + down_read(&b->vm_area.domain->map_lock);
    > + if (ops && !test_bit(CL_locked, &client->flags)) {
    > + set_bit(BK_map_dirty, &b->flags);
    > + set_bit(DM_map_dirty, &client->domain->flags);
    > + } else if (ops) {
    > + if (domain->dev->ops->map(domain, &b->vm_area))
    > + pr_err("%s failed to map locked domain\n", __func__);
    > + }
    > + up_read(&b->vm_area.domain->map_lock);
    > +
    > + return &b->vm_area;
    > +}
    > +
    > +void tegra_iovmm_vm_insert_pfn(struct tegra_iovmm_area *vm,
    > + tegra_iovmm_addr_t vaddr, unsigned long pfn)
    > +{
    > + struct tegra_iovmm_domain *domain = vm->domain;

    Does this need a check for !vm?

    > + BUG_ON(vaddr & ((1<<domain->dev->pgsize_bits)-1));
    > + BUG_ON(vaddr >= vm->iovm_start + vm->iovm_length);
    > + BUG_ON(vaddr < vm->iovm_start);
    > + BUG_ON(vm->ops);
    > +
    > + domain->dev->ops->map_pfn(domain, vm, vaddr, pfn);
    > +}
    > +
    > +void tegra_iovmm_zap_vm(struct tegra_iovmm_area *vm)
    > +{
    > + struct tegra_iovmm_block *b;
    > + struct tegra_iovmm_domain *domain;
    > +
    > + b = container_of(vm, struct tegra_iovmm_block, vm_area);
    > + domain = vm->domain;

    Same.

    > + /*
    > + * if the vm area mapping was deferred, don't unmap it since
    > + * the memory for the page tables it uses may not be allocated
    > + */
    > + down_read(&domain->map_lock);
    > + if (!test_and_clear_bit(BK_map_dirty, &b->flags))
    > + domain->dev->ops->unmap(domain, vm, false);
    > + up_read(&domain->map_lock);
    > +}
    > +
    > +void tegra_iovmm_unzap_vm(struct tegra_iovmm_area *vm)
    > +{
    > + struct tegra_iovmm_block *b;
    > + struct tegra_iovmm_domain *domain;
    > +
    > + b = container_of(vm, struct tegra_iovmm_block, vm_area);
    > + domain = vm->domain;

    Same.

    > + if (!vm->ops)
    > + return;
    > +
    > + down_read(&domain->map_lock);
    > + if (vm->ops) {
    > + if (atomic_read(&domain->locks))
    > + domain->dev->ops->map(domain, vm);
    > + else {
    > + set_bit(BK_map_dirty, &b->flags);
    > + set_bit(DM_map_dirty, &domain->flags);
    > + }
    > + }
    > + up_read(&domain->map_lock);
    > +}
    > +
    > +void tegra_iovmm_free_vm(struct tegra_iovmm_area *vm)
    > +{
    > + struct tegra_iovmm_block *b;
    > + struct tegra_iovmm_domain *domain;
    > +
    > + if (!vm)
    > + return;
    > +
    > + b = container_of(vm, struct tegra_iovmm_block, vm_area);
    > + domain = vm->domain;
    > + down_read(&domain->map_lock);
    > + if (!test_and_clear_bit(BK_map_dirty, &b->flags))
    > + domain->dev->ops->unmap(domain, vm, true);
    > + iovmm_free_block(domain, b);
    > + up_read(&domain->map_lock);
    > +}

    I believe it is more common to initialize b to container_of(...) in the same
    line as the declaration. Since container_of() doesn't actually do any
    dereferencing, it is safe to check for !vm later.

    > +
    > +struct tegra_iovmm_area *tegra_iovmm_area_get(struct tegra_iovmm_area *vm)
    > +{
    > + struct tegra_iovmm_block *b;
    > +
    > + BUG_ON(!vm);
    > + b = container_of(vm, struct tegra_iovmm_block, vm_area);
    > +
    > + atomic_inc(&b->ref);
    > + return &b->vm_area;
    > +}
    > +
    > +void tegra_iovmm_area_put(struct tegra_iovmm_area *vm)
    > +{
    > + struct tegra_iovmm_block *b;
    > + BUG_ON(!vm);
    > + b = container_of(vm, struct tegra_iovmm_block, vm_area);
    > + iovmm_block_put(b);
    > +}
    > +
    > +struct tegra_iovmm_area *tegra_iovmm_find_area_get(
    > + struct tegra_iovmm_client *client, tegra_iovmm_addr_t addr)
    > +{
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b = NULL;
    > +
    > + if (!client)
    > + return NULL;
    > +
    > + spin_lock(&client->domain->block_lock);
    > + n = client->domain->all_blocks.rb_node;
    > +
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, all_node);
    > + if (iovmm_start(b) <= addr && addr <= iovmm_end(b)) {
    > + if (test_bit(BK_free, &b->flags))
    > + b = NULL;
    > + break;
    > + }
    > + if (addr > iovmm_start(b))
    > + n = n->rb_right;
    > + else
    > + n = n->rb_left;
    > + b = NULL;
    > + }
    > + if (b)
    > + atomic_inc(&b->ref);
    > + spin_unlock(&client->domain->block_lock);
    > + if (!b)
    > + return NULL;
    > + return &b->vm_area;
    > +}
    > +
    > +static int _iovmm_client_lock(struct tegra_iovmm_client *client)
    > +{
    > + struct tegra_iovmm_device *dev;
    > + struct tegra_iovmm_domain *domain;
    > + int v;
    > +
    > + if (unlikely(!client))
    > + return -ENODEV;
    > +
    > + if (unlikely(test_bit(CL_locked, &client->flags))) {
    > + pr_err("attempting to relock client %s\n", client->name);
    > + return 0;
    > + }
    > +
    > + domain = client->domain;
    > + dev = domain->dev;
    > + down_write(&domain->map_lock);
    > + v = atomic_inc_return(&domain->locks);
    > + /* if the device doesn't export the lock_domain function, the device
    > + * must guarantee that any valid domain will be locked. */
    > + if (v == 1 && dev->ops->lock_domain) {
    > + if (dev->ops->lock_domain(domain, client)) {
    > + atomic_dec(&domain->locks);
    > + up_write(&domain->map_lock);
    > + return -EAGAIN;
    > + }
    > + }
    > + if (test_and_clear_bit(DM_map_dirty, &domain->flags)) {
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b;
    > +
    > + spin_lock(&domain->block_lock);
    > + n = rb_first(&domain->all_blocks);
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, all_node);
    > + n = rb_next(n);
    > + if (test_bit(BK_free, &b->flags))
    > + continue;
    > +
    > + if (test_and_clear_bit(BK_map_dirty, &b->flags)) {
    > + if (!b->vm_area.ops) {
    > + pr_err("%s: "
    > + "vm_area ops must exist for lazy maps\n",
    > + __func__);
    > + continue;
    > + }
    > + dev->ops->map(domain, &b->vm_area);
    > + }
    > + }
    > + }
    > + set_bit(CL_locked, &client->flags);
    > + up_write(&domain->map_lock);
    > + return 0;
    > +}
    > +
    > +int tegra_iovmm_client_trylock(struct tegra_iovmm_client *client)
    > +{
    > + return _iovmm_client_lock(client);
    > +}
    > +
    > +int tegra_iovmm_client_lock(struct tegra_iovmm_client *client)
    > +{
    > + int ret;
    > +
    > + if (!client)
    > + return -ENODEV;
    > +
    > + ret = wait_event_interruptible(client->domain->delay_lock,
    > + _iovmm_client_lock(client) != -EAGAIN);
    > +
    > + if (ret == -ERESTARTSYS)
    > + return -EINTR;
    > +
    > + return ret;
    > +}
    > +
    > +void tegra_iovmm_client_unlock(struct tegra_iovmm_client *client)
    > +{
    > + struct tegra_iovmm_device *dev;
    > + struct tegra_iovmm_domain *domain;
    > + int do_wake = 0;
    > +
    > + if (!client)
    > + return;
    > +
    > + if (!test_and_clear_bit(CL_locked, &client->flags)) {
    > + pr_err("unlocking unlocked client %s\n", client->name);
    > + return;
    > + }
    > +
    > + domain = client->domain;
    > + dev = domain->dev;
    > + down_write(&domain->map_lock);
    > + if (!atomic_dec_return(&domain->locks)) {
    > + if (dev->ops->unlock_domain)
    > + dev->ops->unlock_domain(domain, client);
    > + do_wake = 1;
    > + }
    > + up_write(&domain->map_lock);
    > + if (do_wake)
    > + wake_up(&domain->delay_lock);
    > +}
    > +
    > +size_t tegra_iovmm_get_vm_size(struct tegra_iovmm_client *client)
    > +{
    > + struct tegra_iovmm_domain *domain;
    > + struct rb_node *n;
    > + struct tegra_iovmm_block *b;
    > + size_t size = 0;
    > +
    > + if (!client)
    > + return 0;
    > +
    > + domain = client->domain;
    > +
    > + spin_lock(&domain->block_lock);
    > + n = rb_first(&domain->all_blocks);
    > + while (n) {
    > + b = rb_entry(n, struct tegra_iovmm_block, all_node);
    > + n = rb_next(n);
    > + size += b->length;
    > + }
    > + spin_unlock(&domain->block_lock);
    > +
    > + return size;
    > +}
    > +
    > +void tegra_iovmm_free_client(struct tegra_iovmm_client *client)
    > +{
    > + struct tegra_iovmm_device *dev;
    > + struct tegra_iovmm_domain *domain;
    > +
    > + if (!client)
    > + return;
    > +
    > + BUG_ON(!client->domain || !client->domain->dev);
    > +
    > + domain = client->domain;
    > + dev = domain->dev;
    > +
    > + if (test_and_clear_bit(CL_locked, &client->flags)) {
    > + pr_err("freeing locked client %s\n", client->name);
    > + if (!atomic_dec_return(&domain->locks)) {
    > + down_write(&domain->map_lock);
    > + if (dev->ops->unlock_domain)
    > + dev->ops->unlock_domain(domain, client);
    > + up_write(&domain->map_lock);
    > + wake_up(&domain->delay_lock);
    > + }
    > + }
    > + mutex_lock(&iovmm_group_list_lock);
    > + if (!atomic_dec_return(&domain->clients))
    > + if (dev->ops->free_domain)
    > + dev->ops->free_domain(domain, client);
    > + list_del(&client->list);
    > + if (list_empty(&client->group->client_list)) {
    > + list_del(&client->group->group_list);
    > + kfree(client->group->name);
    > + kfree(client->group);
    > + }
    > + kfree(client->name);
    > + kfree(client);
    > + mutex_unlock(&iovmm_group_list_lock);
    > +}
    > +
    > +struct tegra_iovmm_client *tegra_iovmm_alloc_client(const char *name,
    > + const char *share_group, struct miscdevice *misc_dev)
    > +{
    > + struct tegra_iovmm_client *c = kzalloc(sizeof(*c), GFP_KERNEL);
    > + struct iovmm_share_group *grp = NULL;
    > + struct tegra_iovmm_device *dev;
    > +
    > + if (!c)
    > + return NULL;
    > + c->name = kstrdup(name, GFP_KERNEL);
    > + if (!c->name)
    > + goto fail;
    > + c->misc_dev = misc_dev;
    > +
    > + mutex_lock(&iovmm_group_list_lock);
    > + if (share_group) {
    > + list_for_each_entry(grp, &iovmm_groups, group_list) {
    > + if (grp->name && !strcmp(grp->name, share_group))
    > + break;
    > + }
    > + }
    > + if (!grp || strcmp(grp->name, share_group)) {
    > + grp = kzalloc(sizeof(*grp), GFP_KERNEL);
    > + if (!grp)
    > + goto fail_lock;
    > + grp->name =
    > + (share_group) ? kstrdup(share_group, GFP_KERNEL) : NULL;

    Parens are not required around "share_group".

    > + if (share_group && !grp->name) {
    > + kfree(grp);
    > + goto fail_lock;
    > + }
    > + list_for_each_entry(dev, &iovmm_devices, list) {
    > + grp->domain = dev->ops->alloc_domain(dev, c);
    > + if (grp->domain)
    > + break;
    > + }
    > + if (!grp->domain) {
    > + pr_err("%s: alloc_domain failed for %s\n",
    > + __func__, c->name);
    > + dump_stack();
    > + kfree(grp->name);
    > + kfree(grp);
    > + grp = NULL;
    > + goto fail_lock;
    > + }
    > + spin_lock_init(&grp->lock);
    > + INIT_LIST_HEAD(&grp->client_list);
    > + list_add_tail(&grp->group_list, &iovmm_groups);
    > + }
    > +
    > + atomic_inc(&grp->domain->clients);
    > + c->group = grp;
    > + c->domain = grp->domain;
    > + spin_lock(&grp->lock);
    > + list_add_tail(&c->list, &grp->client_list);
    > + spin_unlock(&grp->lock);
    > + mutex_unlock(&iovmm_group_list_lock);
    > + return c;
    > +
    > +fail_lock:
    > + mutex_unlock(&iovmm_group_list_lock);
    > +fail:
    > + if (c)
    > + kfree(c->name);
    > + kfree(c);
    > + return NULL;
    > +}
    > +
    > +int tegra_iovmm_register(struct tegra_iovmm_device *dev)
    > +{
    > + BUG_ON(!dev);
    > + mutex_lock(&iovmm_group_list_lock);
    > + if (list_empty(&iovmm_devices)) {
    > + iovmm_cache = KMEM_CACHE(tegra_iovmm_block, 0);
    > + if (!iovmm_cache) {
    > + pr_err("%s: failed to make kmem cache\n", __func__);
    > + mutex_unlock(&iovmm_group_list_lock);
    > + return -ENOMEM;
    > + }
    > + create_proc_read_entry("iovmminfo", S_IRUGO, NULL,
    > + tegra_iovmm_read_proc, NULL);
    > + }
    > + list_add_tail(&dev->list, &iovmm_devices);
    > + mutex_unlock(&iovmm_group_list_lock);
    > + pr_info("%s: added %s\n", __func__, dev->name);
    > + return 0;
    > +}
    > +
    > +int tegra_iovmm_unregister(struct tegra_iovmm_device *dev)
    > +{
    > + mutex_lock(&iovmm_group_list_lock);
    > + list_del(&dev->list);
    > + mutex_unlock(&iovmm_group_list_lock);
    > + return 0;
    > +}
    > +
    > +static int tegra_iovmm_suspend(void)
    > +{
    > + int rc = 0;
    > + struct tegra_iovmm_device *dev;
    > +
    > + list_for_each_entry(dev, &iovmm_devices, list) {
    > +

    Gratuitous newline.

    > + if (!dev->ops->suspend)
    > + continue;
    > +
    > + rc = dev->ops->suspend(dev);
    > + if (rc) {
    > + pr_err("%s: %s suspend returned %d\n",
    > + __func__, dev->name, rc);
    > + return rc;
    > + }
    > + }
    > + return 0;
    > +}
    > +
    > +static void tegra_iovmm_resume(void)
    > +{
    > + struct tegra_iovmm_device *dev;
    > +
    > + list_for_each_entry(dev, &iovmm_devices, list) {
    > + if (dev->ops->resume)
    > + dev->ops->resume(dev);
    > + }
    > +}
    > +
    > +static struct syscore_ops tegra_iovmm_syscore_ops = {
    > + .suspend = tegra_iovmm_suspend,
    > + .resume = tegra_iovmm_resume,
    > +};
    > +
    > +static __init int tegra_iovmm_syscore_init(void)
    > +{
    > + register_syscore_ops(&tegra_iovmm_syscore_ops);
    > + return 0;
    > +}
    > +subsys_initcall(tegra_iovmm_syscore_init);
    > --
    > 1.7.0.4
    >
    > --
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    >
    >
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