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authorMikulas Patocka <mpatocka@redhat.com>2017-04-30 17:32:28 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-25 14:30:08 +0200
commitea4889d6f39ddeb4f0ac87fc935a794db94b7895 (patch)
treeab54d81629c6b46775a45627418cfa5bdee66355 /drivers/md
parent4a9631ffe5205583800d8bdf9735381f0a09324d (diff)
dm bufio: make the parameter "retain_bytes" unsigned long
commit 13840d38016203f0095cd547b90352812d24b787 upstream. Change the type of the parameter "retain_bytes" from unsigned to unsigned long, so that on 64-bit machines the user can set more than 4GiB of data to be retained. Also, change the type of the variable "count" in the function "__evict_old_buffers" to unsigned long. The assignment "count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY];" could result in unsigned long to unsigned overflow and that could result in buffers not being freed when they should. While at it, avoid division in get_retain_buffers(). Division is slow, we can change it to shift because we have precalculated the log2 of block size. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-bufio.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index f04a1566df81..cdceefd0e57d 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -222,7 +222,7 @@ static DEFINE_SPINLOCK(param_spinlock);
* Buffers are freed after this timeout
*/
static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS;
-static unsigned dm_bufio_retain_bytes = DM_BUFIO_DEFAULT_RETAIN_BYTES;
+static unsigned long dm_bufio_retain_bytes = DM_BUFIO_DEFAULT_RETAIN_BYTES;
static unsigned long dm_bufio_peak_allocated;
static unsigned long dm_bufio_allocated_kmem_cache;
@@ -1514,10 +1514,10 @@ static bool __try_evict_buffer(struct dm_buffer *b, gfp_t gfp)
return true;
}
-static unsigned get_retain_buffers(struct dm_bufio_client *c)
+static unsigned long get_retain_buffers(struct dm_bufio_client *c)
{
- unsigned retain_bytes = ACCESS_ONCE(dm_bufio_retain_bytes);
- return retain_bytes / c->block_size;
+ unsigned long retain_bytes = ACCESS_ONCE(dm_bufio_retain_bytes);
+ return retain_bytes >> (c->sectors_per_block_bits + SECTOR_SHIFT);
}
static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
@@ -1527,7 +1527,7 @@ static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
struct dm_buffer *b, *tmp;
unsigned long freed = 0;
unsigned long count = nr_to_scan;
- unsigned retain_target = get_retain_buffers(c);
+ unsigned long retain_target = get_retain_buffers(c);
for (l = 0; l < LIST_SIZE; l++) {
list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) {
@@ -1753,8 +1753,8 @@ static bool older_than(struct dm_buffer *b, unsigned long age_hz)
static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz)
{
struct dm_buffer *b, *tmp;
- unsigned retain_target = get_retain_buffers(c);
- unsigned count;
+ unsigned long retain_target = get_retain_buffers(c);
+ unsigned long count;
LIST_HEAD(write_list);
dm_bufio_lock(c);
@@ -1915,7 +1915,7 @@ MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache");
module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds");
-module_param_named(retain_bytes, dm_bufio_retain_bytes, uint, S_IRUGO | S_IWUSR);
+module_param_named(retain_bytes, dm_bufio_retain_bytes, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(retain_bytes, "Try to keep at least this many bytes cached in memory");
module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR);