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Subject[PATCH 4.9 092/104] xfs: remove kmem_zalloc_greedy
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Darrick J. Wong" <darrick.wong@oracle.com>


[ Upstream commit 08b005f1333154ae5b404ca28766e0ffb9f1c150 ]

The sole remaining caller of kmem_zalloc_greedy is bulkstat, which uses
it to grab 1-4 pages for staging of inobt records. The infinite loop in
the greedy allocation function is causing hangs[1] in generic/269, so
just get rid of the greedy allocator in favor of kmem_zalloc_large.
This makes bulkstat somewhat more likely to ENOMEM if there's really no
pages to spare, but eliminates a source of hangs.

[1] http://lkml.kernel.org/r/20170301044634.rgidgdqqiiwsmfpj%40XZHOUW.usersys.redhat.com

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v2: remove single-page fallback

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/xfs/kmem.c | 18 ------------------
fs/xfs/kmem.h | 2 --
fs/xfs/xfs_itable.c | 6 ++----
3 files changed, 2 insertions(+), 24 deletions(-)

--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -24,24 +24,6 @@
#include "kmem.h"
#include "xfs_message.h"

-/*
- * Greedy allocation. May fail and may return vmalloced memory.
- */
-void *
-kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize)
-{
- void *ptr;
- size_t kmsize = maxsize;
-
- while (!(ptr = vzalloc(kmsize))) {
- if ((kmsize >>= 1) <= minsize)
- kmsize = minsize;
- }
- if (ptr)
- *size = kmsize;
- return ptr;
-}
-
void *
kmem_alloc(size_t size, xfs_km_flags_t flags)
{
--- a/fs/xfs/kmem.h
+++ b/fs/xfs/kmem.h
@@ -69,8 +69,6 @@ static inline void kmem_free(const void
}


-extern void *kmem_zalloc_greedy(size_t *, size_t, size_t);
-
static inline void *
kmem_zalloc(size_t size, xfs_km_flags_t flags)
{
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -361,7 +361,6 @@ xfs_bulkstat(
xfs_agino_t agino; /* inode # in allocation group */
xfs_agnumber_t agno; /* allocation group number */
xfs_btree_cur_t *cur; /* btree cursor for ialloc btree */
- size_t irbsize; /* size of irec buffer in bytes */
xfs_inobt_rec_incore_t *irbuf; /* start of irec buffer */
int nirbuf; /* size of irbuf */
int ubcount; /* size of user's buffer */
@@ -388,11 +387,10 @@ xfs_bulkstat(
*ubcountp = 0;
*done = 0;

- irbuf = kmem_zalloc_greedy(&irbsize, PAGE_SIZE, PAGE_SIZE * 4);
+ irbuf = kmem_zalloc_large(PAGE_SIZE * 4, KM_SLEEP);
if (!irbuf)
return -ENOMEM;
-
- nirbuf = irbsize / sizeof(*irbuf);
+ nirbuf = (PAGE_SIZE * 4) / sizeof(*irbuf);

/*
* Loop over the allocation groups, starting from the last

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