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Subject[patch 25/45] SCSI: sg: fix races during device removal
-stable review patch.  If anyone has any objections, please let us know.
---------------------
From: Tony Battersby <tonyb@cybernetics.com>

upstream commit: c6517b7942fad663cc1cf3235cbe4207cf769332

sg has the following problems related to device removal:

* opening a sg fd races with removing a device
* closing a sg fd races with removing a device
* /proc/scsi/sg/* access races with removing a device
* command completion races with removing a device
* command completion races with closing a sg fd
* can rmmod sg with active commands
These problems can cause kernel oopses, memory-use-after-free, or
double-free errors. This patch fixes these problems by using krefs
to manage the lifetime of sg_device and sg_fd.

Each command submitted to the midlevel holds a reference to sg_fd
until the completion callback. This ensures that sg_fd doesn't go
away if the fd is closed with commands still outstanding.

sg_fd gets the reference of sg_device (with scsi_device) and also
makes sure that the sg module doesn't go away.

/proc/scsi/sg/* functions don't play nicely with krefs because they
give information about sg_fds which have been closed but not yet
freed due to still having outstanding commands and sg_devices which
have been removed but not yet freed due to still being referenced
by one or more sg_fds. To deal with this safely without removing
functionality, /proc functions now access sg_device and sg_fd while
holding a lock instead of using kref_get()/kref_put().
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
drivers/scsi/sg.c | 418 +++++++++++++++++++++++++-----------------------------
1 file changed, 201 insertions(+), 217 deletions(-)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -101,6 +101,7 @@ static int scatter_elem_sz_prev = SG_SCA
#define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)

static int sg_add(struct device *, struct class_interface *);
+static void sg_device_destroy(struct kref *kref);
static void sg_remove(struct device *, struct class_interface *);

static DEFINE_IDR(sg_index_idr);
@@ -158,6 +159,8 @@ typedef struct sg_fd { /* holds the sta
char next_cmd_len; /* 0 -> automatic (def), >0 -> use on next write() */
char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
char mmap_called; /* 0 -> mmap() never called on this fd */
+ struct kref f_ref;
+ struct execute_work ew;
} Sg_fd;

typedef struct sg_device { /* holds the state of each scsi generic device */
@@ -171,6 +174,7 @@ typedef struct sg_device { /* holds the
char sgdebug; /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
struct gendisk *disk;
struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
+ struct kref d_ref;
} Sg_device;

static int sg_fasync(int fd, struct file *filp, int mode);
@@ -194,13 +198,14 @@ static void sg_build_reserve(Sg_fd * sfp
static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
-static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
-static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
+static void sg_remove_sfp(struct kref *);
static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
static Sg_request *sg_add_request(Sg_fd * sfp);
static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
static int sg_res_in_use(Sg_fd * sfp);
+static Sg_device *sg_lookup_dev(int dev);
static Sg_device *sg_get_dev(int dev);
+static void sg_put_dev(Sg_device *sdp);
#ifdef CONFIG_SCSI_PROC_FS
static int sg_last_dev(void);
#endif
@@ -237,22 +242,17 @@ sg_open(struct inode *inode, struct file
nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
sdp = sg_get_dev(dev);
- if ((!sdp) || (!sdp->device)) {
- unlock_kernel();
- return -ENXIO;
- }
- if (sdp->detached) {
- unlock_kernel();
- return -ENODEV;
+ if (IS_ERR(sdp)) {
+ retval = PTR_ERR(sdp);
+ sdp = NULL;
+ goto sg_put;
}

/* This driver's module count bumped by fops_get in <linux/fs.h> */
/* Prevent the device driver from vanishing while we sleep */
retval = scsi_device_get(sdp->device);
- if (retval) {
- unlock_kernel();
- return retval;
- }
+ if (retval)
+ goto sg_put;

if (!((flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device))) {
@@ -303,16 +303,20 @@ sg_open(struct inode *inode, struct file
if ((sfp = sg_add_sfp(sdp, dev)))
filp->private_data = sfp;
else {
- if (flags & O_EXCL)
+ if (flags & O_EXCL) {
sdp->exclude = 0; /* undo if error */
+ wake_up_interruptible(&sdp->o_excl_wait);
+ }
retval = -ENOMEM;
goto error_out;
}
- unlock_kernel();
- return 0;
-
- error_out:
- scsi_device_put(sdp->device);
+ retval = 0;
+error_out:
+ if (retval)
+ scsi_device_put(sdp->device);
+sg_put:
+ if (sdp)
+ sg_put_dev(sdp);
unlock_kernel();
return retval;
}
@@ -327,13 +331,13 @@ sg_release(struct inode *inode, struct f
if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
- if (0 == sg_remove_sfp(sdp, sfp)) { /* Returns 1 when sdp gone */
- if (!sdp->detached) {
- scsi_device_put(sdp->device);
- }
- sdp->exclude = 0;
- wake_up_interruptible(&sdp->o_excl_wait);
- }
+
+ sfp->closed = 1;
+
+ sdp->exclude = 0;
+ wake_up_interruptible(&sdp->o_excl_wait);
+
+ kref_put(&sfp->f_ref, sg_remove_sfp);
return 0;
}

@@ -755,6 +759,7 @@ sg_common_write(Sg_fd * sfp, Sg_request
hp->duration = jiffies_to_msecs(jiffies);

srp->rq->timeout = timeout;
+ kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
srp->rq, 1, sg_rq_end_io);
return 0;
@@ -1247,24 +1252,23 @@ sg_mmap(struct file *filp, struct vm_are
static void sg_rq_end_io(struct request *rq, int uptodate)
{
struct sg_request *srp = rq->end_io_data;
- Sg_device *sdp = NULL;
+ Sg_device *sdp;
Sg_fd *sfp;
unsigned long iflags;
unsigned int ms;
char *sense;
- int result, resid;
+ int result, resid, done = 1;

- if (NULL == srp) {
- printk(KERN_ERR "sg_cmd_done: NULL request\n");
+ if (WARN_ON(srp->done != 0))
return;
- }
+
sfp = srp->parentfp;
- if (sfp)
- sdp = sfp->parentdp;
- if ((NULL == sdp) || sdp->detached) {
- printk(KERN_INFO "sg_cmd_done: device detached\n");
+ if (WARN_ON(sfp == NULL))
return;
- }
+
+ sdp = sfp->parentdp;
+ if (unlikely(sdp->detached))
+ printk(KERN_INFO "sg_rq_end_io: device detached\n");

sense = rq->sense;
result = rq->errors;
@@ -1303,33 +1307,26 @@ static void sg_rq_end_io(struct request
}
/* Rely on write phase to clean out srp status values, so no "else" */

- if (sfp->closed) { /* whoops this fd already released, cleanup */
- SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
- sg_finish_rem_req(srp);
- srp = NULL;
- if (NULL == sfp->headrp) {
- SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, final cleanup\n"));
- if (0 == sg_remove_sfp(sdp, sfp)) { /* device still present */
- scsi_device_put(sdp->device);
- }
- sfp = NULL;
- }
- } else if (srp && srp->orphan) {
+ write_lock_irqsave(&sfp->rq_list_lock, iflags);
+ if (unlikely(srp->orphan)) {
if (sfp->keep_orphan)
srp->sg_io_owned = 0;
- else {
- sg_finish_rem_req(srp);
- srp = NULL;
- }
+ else
+ done = 0;
}
- if (sfp && srp) {
- /* Now wake up any sg_read() that is waiting for this packet. */
- kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
- write_lock_irqsave(&sfp->rq_list_lock, iflags);
- srp->done = 1;
+ srp->done = done;
+ write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+
+ if (likely(done)) {
+ /* Now wake up any sg_read() that is waiting for this
+ * packet.
+ */
wake_up_interruptible(&sfp->read_wait);
- write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- }
+ kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
+ } else
+ sg_finish_rem_req(srp); /* call with srp->done == 0 */
+
+ kref_put(&sfp->f_ref, sg_remove_sfp);
}

static struct file_operations sg_fops = {
@@ -1364,17 +1361,18 @@ static Sg_device *sg_alloc(struct gendis
printk(KERN_WARNING "kmalloc Sg_device failure\n");
return ERR_PTR(-ENOMEM);
}
- error = -ENOMEM;
+
if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
printk(KERN_WARNING "idr expansion Sg_device failure\n");
+ error = -ENOMEM;
goto out;
}

write_lock_irqsave(&sg_index_lock, iflags);
- error = idr_get_new(&sg_index_idr, sdp, &k);
- write_unlock_irqrestore(&sg_index_lock, iflags);

+ error = idr_get_new(&sg_index_idr, sdp, &k);
if (error) {
+ write_unlock_irqrestore(&sg_index_lock, iflags);
printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
error);
goto out;
@@ -1391,6 +1389,9 @@ static Sg_device *sg_alloc(struct gendis
init_waitqueue_head(&sdp->o_excl_wait);
sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
sdp->index = k;
+ kref_init(&sdp->d_ref);
+
+ write_unlock_irqrestore(&sg_index_lock, iflags);

error = 0;
out:
@@ -1401,6 +1402,8 @@ static Sg_device *sg_alloc(struct gendis
return sdp;

overflow:
+ idr_remove(&sg_index_idr, k);
+ write_unlock_irqrestore(&sg_index_lock, iflags);
sdev_printk(KERN_WARNING, scsidp,
"Unable to attach sg device type=%d, minor "
"number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
@@ -1488,49 +1491,46 @@ out:
return error;
}

-static void
-sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
+static void sg_device_destroy(struct kref *kref)
+{
+ struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
+ unsigned long flags;
+
+ /* CAUTION! Note that the device can still be found via idr_find()
+ * even though the refcount is 0. Therefore, do idr_remove() BEFORE
+ * any other cleanup.
+ */
+
+ write_lock_irqsave(&sg_index_lock, flags);
+ idr_remove(&sg_index_idr, sdp->index);
+ write_unlock_irqrestore(&sg_index_lock, flags);
+
+ SCSI_LOG_TIMEOUT(3,
+ printk("sg_device_destroy: %s\n",
+ sdp->disk->disk_name));
+
+ put_disk(sdp->disk);
+ kfree(sdp);
+}
+
+static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
{
struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
Sg_device *sdp = dev_get_drvdata(cl_dev);
unsigned long iflags;
Sg_fd *sfp;
- Sg_fd *tsfp;
- Sg_request *srp;
- Sg_request *tsrp;
- int delay;

- if (!sdp)
+ if (!sdp || sdp->detached)
return;

- delay = 0;
+ SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));
+
+ /* Need a write lock to set sdp->detached. */
write_lock_irqsave(&sg_index_lock, iflags);
- if (sdp->headfp) {
- sdp->detached = 1;
- for (sfp = sdp->headfp; sfp; sfp = tsfp) {
- tsfp = sfp->nextfp;
- for (srp = sfp->headrp; srp; srp = tsrp) {
- tsrp = srp->nextrp;
- if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
- sg_finish_rem_req(srp);
- }
- if (sfp->closed) {
- scsi_device_put(sdp->device);
- __sg_remove_sfp(sdp, sfp);
- } else {
- delay = 1;
- wake_up_interruptible(&sfp->read_wait);
- kill_fasync(&sfp->async_qp, SIGPOLL,
- POLL_HUP);
- }
- }
- SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d, dirty\n", sdp->index));
- if (NULL == sdp->headfp) {
- idr_remove(&sg_index_idr, sdp->index);
- }
- } else { /* nothing active, simple case */
- SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d\n", sdp->index));
- idr_remove(&sg_index_idr, sdp->index);
+ sdp->detached = 1;
+ for (sfp = sdp->headfp; sfp; sfp = sfp->nextfp) {
+ wake_up_interruptible(&sfp->read_wait);
+ kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
}
write_unlock_irqrestore(&sg_index_lock, iflags);

@@ -1538,13 +1538,8 @@ sg_remove(struct device *cl_dev, struct
device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
cdev_del(sdp->cdev);
sdp->cdev = NULL;
- put_disk(sdp->disk);
- sdp->disk = NULL;
- if (NULL == sdp->headfp)
- kfree(sdp);

- if (delay)
- msleep(10); /* dirty detach so delay device destruction */
+ sg_put_dev(sdp);
}

module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
@@ -1941,22 +1936,6 @@ sg_get_rq_mark(Sg_fd * sfp, int pack_id)
return resp;
}

-#ifdef CONFIG_SCSI_PROC_FS
-static Sg_request *
-sg_get_nth_request(Sg_fd * sfp, int nth)
-{
- Sg_request *resp;
- unsigned long iflags;
- int k;
-
- read_lock_irqsave(&sfp->rq_list_lock, iflags);
- for (k = 0, resp = sfp->headrp; resp && (k < nth);
- ++k, resp = resp->nextrp) ;
- read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- return resp;
-}
-#endif
-
/* always adds to end of list */
static Sg_request *
sg_add_request(Sg_fd * sfp)
@@ -2032,22 +2011,6 @@ sg_remove_request(Sg_fd * sfp, Sg_reques
return res;
}

-#ifdef CONFIG_SCSI_PROC_FS
-static Sg_fd *
-sg_get_nth_sfp(Sg_device * sdp, int nth)
-{
- Sg_fd *resp;
- unsigned long iflags;
- int k;
-
- read_lock_irqsave(&sg_index_lock, iflags);
- for (k = 0, resp = sdp->headfp; resp && (k < nth);
- ++k, resp = resp->nextfp) ;
- read_unlock_irqrestore(&sg_index_lock, iflags);
- return resp;
-}
-#endif
-
static Sg_fd *
sg_add_sfp(Sg_device * sdp, int dev)
{
@@ -2062,6 +2025,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);

+ kref_init(&sfp->f_ref);
sfp->timeout = SG_DEFAULT_TIMEOUT;
sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
sfp->force_packid = SG_DEF_FORCE_PACK_ID;
@@ -2089,15 +2053,54 @@ sg_add_sfp(Sg_device * sdp, int dev)
sg_build_reserve(sfp, bufflen);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
sfp->reserve.bufflen, sfp->reserve.k_use_sg));
+
+ kref_get(&sdp->d_ref);
+ __module_get(THIS_MODULE);
return sfp;
}

-static void
-__sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
+static void sg_remove_sfp_usercontext(struct work_struct *work)
+{
+ struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
+ struct sg_device *sdp = sfp->parentdp;
+
+ /* Cleanup any responses which were never read(). */
+ while (sfp->headrp)
+ sg_finish_rem_req(sfp->headrp);
+
+ if (sfp->reserve.bufflen > 0) {
+ SCSI_LOG_TIMEOUT(6,
+ printk("sg_remove_sfp: bufflen=%d, k_use_sg=%d\n",
+ (int) sfp->reserve.bufflen,
+ (int) sfp->reserve.k_use_sg));
+ sg_remove_scat(&sfp->reserve);
+ }
+
+ SCSI_LOG_TIMEOUT(6,
+ printk("sg_remove_sfp: %s, sfp=0x%p\n",
+ sdp->disk->disk_name,
+ sfp));
+ kfree(sfp);
+
+ scsi_device_put(sdp->device);
+ sg_put_dev(sdp);
+ module_put(THIS_MODULE);
+}
+
+static void sg_remove_sfp(struct kref *kref)
{
+ struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
+ struct sg_device *sdp = sfp->parentdp;
Sg_fd *fp;
Sg_fd *prev_fp;
+ unsigned long iflags;
+
+ /* CAUTION! Note that sfp can still be found by walking sdp->headfp
+ * even though the refcount is now 0. Therefore, unlink sfp from
+ * sdp->headfp BEFORE doing any other cleanup.
+ */

+ write_lock_irqsave(&sg_index_lock, iflags);
prev_fp = sdp->headfp;
if (sfp == prev_fp)
sdp->headfp = prev_fp->nextfp;
@@ -2110,54 +2113,10 @@ __sg_remove_sfp(Sg_device * sdp, Sg_fd *
prev_fp = fp;
}
}
- if (sfp->reserve.bufflen > 0) {
- SCSI_LOG_TIMEOUT(6,
- printk("__sg_remove_sfp: bufflen=%d, k_use_sg=%d\n",
- (int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
- sg_remove_scat(&sfp->reserve);
- }
- sfp->parentdp = NULL;
- SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp: sfp=0x%p\n", sfp));
- kfree(sfp);
-}
-
-/* Returns 0 in normal case, 1 when detached and sdp object removed */
-static int
-sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
-{
- Sg_request *srp;
- Sg_request *tsrp;
- int dirty = 0;
- int res = 0;
-
- for (srp = sfp->headrp; srp; srp = tsrp) {
- tsrp = srp->nextrp;
- if (sg_srp_done(srp, sfp))
- sg_finish_rem_req(srp);
- else
- ++dirty;
- }
- if (0 == dirty) {
- unsigned long iflags;
+ write_unlock_irqrestore(&sg_index_lock, iflags);
+ wake_up_interruptible(&sdp->o_excl_wait);

- write_lock_irqsave(&sg_index_lock, iflags);
- __sg_remove_sfp(sdp, sfp);
- if (sdp->detached && (NULL == sdp->headfp)) {
- idr_remove(&sg_index_idr, sdp->index);
- kfree(sdp);
- res = 1;
- }
- write_unlock_irqrestore(&sg_index_lock, iflags);
- } else {
- /* MOD_INC's to inhibit unloading sg and associated adapter driver */
- /* only bump the access_count if we actually succeeded in
- * throwing another counter on the host module */
- scsi_device_get(sdp->device); /* XXX: retval ignored? */
- sfp->closed = 1; /* flag dirty state on this fd */
- SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
- dirty));
- }
- return res;
+ execute_in_process_context(sg_remove_sfp_usercontext, &sfp->ew);
}

static int
@@ -2199,19 +2158,38 @@ sg_last_dev(void)
}
#endif

-static Sg_device *
-sg_get_dev(int dev)
+/* must be called with sg_index_lock held */
+static Sg_device *sg_lookup_dev(int dev)
{
- Sg_device *sdp;
- unsigned long iflags;
+ return idr_find(&sg_index_idr, dev);
+}

- read_lock_irqsave(&sg_index_lock, iflags);
- sdp = idr_find(&sg_index_idr, dev);
- read_unlock_irqrestore(&sg_index_lock, iflags);
+static Sg_device *sg_get_dev(int dev)
+{
+ struct sg_device *sdp;
+ unsigned long flags;
+
+ read_lock_irqsave(&sg_index_lock, flags);
+ sdp = sg_lookup_dev(dev);
+ if (!sdp)
+ sdp = ERR_PTR(-ENXIO);
+ else if (sdp->detached) {
+ /* If sdp->detached, then the refcount may already be 0, in
+ * which case it would be a bug to do kref_get().
+ */
+ sdp = ERR_PTR(-ENODEV);
+ } else
+ kref_get(&sdp->d_ref);
+ read_unlock_irqrestore(&sg_index_lock, flags);

return sdp;
}

+static void sg_put_dev(struct sg_device *sdp)
+{
+ kref_put(&sdp->d_ref, sg_device_destroy);
+}
+
#ifdef CONFIG_SCSI_PROC_FS

static struct proc_dir_entry *sg_proc_sgp = NULL;
@@ -2468,8 +2446,10 @@ static int sg_proc_seq_show_dev(struct s
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
struct scsi_device *scsidp;
+ unsigned long iflags;

- sdp = it ? sg_get_dev(it->index) : NULL;
+ read_lock_irqsave(&sg_index_lock, iflags);
+ sdp = it ? sg_lookup_dev(it->index) : NULL;
if (sdp && (scsidp = sdp->device) && (!sdp->detached))
seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
scsidp->host->host_no, scsidp->channel,
@@ -2480,6 +2460,7 @@ static int sg_proc_seq_show_dev(struct s
(int) scsi_device_online(scsidp));
else
seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
+ read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}

@@ -2493,16 +2474,20 @@ static int sg_proc_seq_show_devstrs(stru
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
struct scsi_device *scsidp;
+ unsigned long iflags;

- sdp = it ? sg_get_dev(it->index) : NULL;
+ read_lock_irqsave(&sg_index_lock, iflags);
+ sdp = it ? sg_lookup_dev(it->index) : NULL;
if (sdp && (scsidp = sdp->device) && (!sdp->detached))
seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
scsidp->vendor, scsidp->model, scsidp->rev);
else
seq_printf(s, "<no active device>\n");
+ read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}

+/* must be called while holding sg_index_lock */
static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
{
int k, m, new_interface, blen, usg;
@@ -2512,7 +2497,8 @@ static void sg_proc_debug_helper(struct
const char * cp;
unsigned int ms;

- for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
+ for (k = 0, fp = sdp->headfp; fp != NULL; ++k, fp = fp->nextfp) {
+ read_lock(&fp->rq_list_lock); /* irqs already disabled */
seq_printf(s, " FD(%d): timeout=%dms bufflen=%d "
"(res)sgat=%d low_dma=%d\n", k + 1,
jiffies_to_msecs(fp->timeout),
@@ -2522,7 +2508,9 @@ static void sg_proc_debug_helper(struct
seq_printf(s, " cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
(int) fp->cmd_q, (int) fp->force_packid,
(int) fp->keep_orphan, (int) fp->closed);
- for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
+ for (m = 0, srp = fp->headrp;
+ srp != NULL;
+ ++m, srp = srp->nextrp) {
hp = &srp->header;
new_interface = (hp->interface_id == '\0') ? 0 : 1;
if (srp->res_used) {
@@ -2559,6 +2547,7 @@ static void sg_proc_debug_helper(struct
}
if (0 == m)
seq_printf(s, " No requests active\n");
+ read_unlock(&fp->rq_list_lock);
}
}

@@ -2571,39 +2560,34 @@ static int sg_proc_seq_show_debug(struct
{
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
+ unsigned long iflags;

if (it && (0 == it->index)) {
seq_printf(s, "max_active_device=%d(origin 1)\n",
(int)it->max);
seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
}
- sdp = it ? sg_get_dev(it->index) : NULL;
- if (sdp) {
- struct scsi_device *scsidp = sdp->device;

- if (NULL == scsidp) {
- seq_printf(s, "device %d detached ??\n",
- (int)it->index);
- return 0;
- }
+ read_lock_irqsave(&sg_index_lock, iflags);
+ sdp = it ? sg_lookup_dev(it->index) : NULL;
+ if (sdp && sdp->headfp) {
+ struct scsi_device *scsidp = sdp->device;

- if (sg_get_nth_sfp(sdp, 0)) {
- seq_printf(s, " >>> device=%s ",
- sdp->disk->disk_name);
- if (sdp->detached)
- seq_printf(s, "detached pending close ");
- else
- seq_printf
- (s, "scsi%d chan=%d id=%d lun=%d em=%d",
- scsidp->host->host_no,
- scsidp->channel, scsidp->id,
- scsidp->lun,
- scsidp->host->hostt->emulated);
- seq_printf(s, " sg_tablesize=%d excl=%d\n",
- sdp->sg_tablesize, sdp->exclude);
- }
+ seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
+ if (sdp->detached)
+ seq_printf(s, "detached pending close ");
+ else
+ seq_printf
+ (s, "scsi%d chan=%d id=%d lun=%d em=%d",
+ scsidp->host->host_no,
+ scsidp->channel, scsidp->id,
+ scsidp->lun,
+ scsidp->host->hostt->emulated);
+ seq_printf(s, " sg_tablesize=%d excl=%d\n",
+ sdp->sg_tablesize, sdp->exclude);
sg_proc_debug_helper(s, sdp);
}
+ read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}



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  Last update: 2009-04-01 01:25    [from the cache]
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