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authorMing Lei <ming.lei@canonical.com>2013-02-27 17:05:19 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-27 19:10:21 -0800
commitac2e5327a5e4f6477afc6a3b3b0dc6e0476d71d4 (patch)
treee8193241c1789655f2168013d1ee434c21f12bac /block/partitions
parent06004e6eebdaf101a0f9b533fac77b5768d2c09c (diff)
downloadlinux-linaro-stable-ac2e5327a5e4f6477afc6a3b3b0dc6e0476d71d4.tar.gz
block/partitions: optimize memory allocation in check_partition()
Currently, sizeof(struct parsed_partitions) may be 64KB in 32bit arch, so it is easy to trigger page allocation failure by check_partition, especially in hotplug block device situation(such as, USB mass storage, MMC card, ...), and Felipe Balbi has observed the failure. This patch does below optimizations on the allocation of struct parsed_partitions to try to address the issue: - make parsed_partitions.parts as pointer so that the pointed memory can fit in 32KB buffer, then approximate 32KB memory can be saved - vmalloc the buffer pointed by parsed_partitions.parts because 32KB is still a bit big for kmalloc - given that many devices have the partition count limit, so only allocate disk_max_parts() partitions instead of 256 partitions always Signed-off-by: Ming Lei <ming.lei@canonical.com> Reported-by: Felipe Balbi <balbi@ti.com> Cc: Jens Axboe <axboe@kernel.dk> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block/partitions')
-rw-r--r--block/partitions/check.c37
-rw-r--r--block/partitions/check.h4
2 files changed, 35 insertions, 6 deletions
diff --git a/block/partitions/check.c b/block/partitions/check.c
index bc908672c976..19ba207ea7d1 100644
--- a/block/partitions/check.c
+++ b/block/partitions/check.c
@@ -14,6 +14,7 @@
*/
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
@@ -106,18 +107,45 @@ static int (*check_part[])(struct parsed_partitions *) = {
NULL
};
+static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
+{
+ struct parsed_partitions *state;
+ int nr;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return NULL;
+
+ nr = disk_max_parts(hd);
+ state->parts = vzalloc(nr * sizeof(state->parts[0]));
+ if (!state->parts) {
+ kfree(state);
+ return NULL;
+ }
+
+ state->limit = nr;
+
+ return state;
+}
+
+void free_partitions(struct parsed_partitions *state)
+{
+ vfree(state->parts);
+ kfree(state);
+}
+
struct parsed_partitions *
check_partition(struct gendisk *hd, struct block_device *bdev)
{
struct parsed_partitions *state;
int i, res, err;
- state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
+ state = allocate_partitions(hd);
if (!state)
return NULL;
state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
if (!state->pp_buf) {
- kfree(state);
+ free_partitions(state);
return NULL;
}
state->pp_buf[0] = '\0';
@@ -128,10 +156,9 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
if (isdigit(state->name[strlen(state->name)-1]))
sprintf(state->name, "p");
- state->limit = disk_max_parts(hd);
i = res = err = 0;
while (!res && check_part[i]) {
- memset(&state->parts, 0, sizeof(state->parts));
+ memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
res = check_part[i++](state);
if (res < 0) {
/* We have hit an I/O error which we don't report now.
@@ -161,6 +188,6 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
printk(KERN_INFO "%s", state->pp_buf);
free_page((unsigned long)state->pp_buf);
- kfree(state);
+ free_partitions(state);
return ERR_PTR(res);
}
diff --git a/block/partitions/check.h b/block/partitions/check.h
index 52b100311ec3..eade17ea910b 100644
--- a/block/partitions/check.h
+++ b/block/partitions/check.h
@@ -15,13 +15,15 @@ struct parsed_partitions {
int flags;
bool has_info;
struct partition_meta_info info;
- } parts[DISK_MAX_PARTS];
+ } *parts;
int next;
int limit;
bool access_beyond_eod;
char *pp_buf;
};
+void free_partitions(struct parsed_partitions *state);
+
struct parsed_partitions *
check_partition(struct gendisk *, struct block_device *);