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authorTheodore Ts'o <tytso@mit.edu>2013-11-08 06:14:53 +0100
committerTheodore Ts'o <tytso@mit.edu>2013-11-08 06:14:53 +0100
commitdd1f723bf56bd96efc9d90e9e60dc511c79de48f (patch)
tree3860500165c69c225ccd5121f2ffde93dfbf4f02 /fs
parentext4: remove unreachable code after ext4_can_extents_be_merged() (diff)
downloadlinux-dd1f723bf56bd96efc9d90e9e60dc511c79de48f.tar.xz
linux-dd1f723bf56bd96efc9d90e9e60dc511c79de48f.zip
ext4: use prandom_u32() instead of get_random_bytes()
Many of the uses of get_random_bytes() do not actually need cryptographically secure random numbers. Replace those uses with a call to prandom_u32(), which is faster and which doesn't consume entropy from the /dev/random driver. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/ialloc.c2
-rw-r--r--fs/ext4/mmp.c2
-rw-r--r--fs/ext4/super.c7
3 files changed, 4 insertions, 7 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 137193ff389b..0ee59a6644e2 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -432,7 +432,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
grp = hinfo.hash;
} else
- get_random_bytes(&grp, sizeof(grp));
+ grp = prandom_u32();
parent_group = (unsigned)grp % ngroups;
for (i = 0; i < ngroups; i++) {
g = (parent_group + i) % ngroups;
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 214461e42a05..04434ad3e8e0 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -259,7 +259,7 @@ static unsigned int mmp_new_seq(void)
u32 new_seq;
do {
- get_random_bytes(&new_seq, sizeof(u32));
+ new_seq = prandom_u32();
} while (new_seq > EXT4_MMP_SEQ_MAX);
return new_seq;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d3a857bfae47..c977f4e4e63b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3068,7 +3068,6 @@ static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_li_request *elr;
- unsigned long rnd;
elr = kzalloc(sizeof(*elr), GFP_KERNEL);
if (!elr)
@@ -3083,10 +3082,8 @@ static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
* spread the inode table initialization requests
* better.
*/
- get_random_bytes(&rnd, sizeof(rnd));
- elr->lr_next_sched = jiffies + (unsigned long)rnd %
- (EXT4_DEF_LI_MAX_START_DELAY * HZ);
-
+ elr->lr_next_sched = jiffies + (prandom_u32() %
+ (EXT4_DEF_LI_MAX_START_DELAY * HZ));
return elr;
}