c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2025-01-12 19:20:28 +03:00
Code Issues Packages Projects Releases Wiki Activity

kmem-cache: spl_kmem_cache_create() may always sleep

Browse Source 
When this code was originally written I went overboard and allowed
for the possibility of creating a cache in an atomic context.  In
practice there are no callers which ever do this.  This makes sense
since a cache is by design a long lived data structure.

To prevent abuse of this function going forward I'm removing the
code which is supported to handle an atomic context.  All allocators
have been updated to use KM_SLEEP and the might_sleep() debug macro
has been added to immediately detect atomic callers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Brian Behlendorf 2012-12-10 11:01:08 -08:00
parent a5a98e7260
commit 296a8e596d
1 changed files with 8 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
module/spl/spl-kmem.c
View File

@ -1482,7 +1482,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
void *priv, void *vmp, int flags)
{
spl_kmem_cache_t *skc;
int rc, kmem_flags = KM_SLEEP;
int rc;
SENTRY;
ASSERTF(!(flags & KMC_NOMAGAZINE), "Bad KMC_NOMAGAZINE (%x)\n", flags);
@ -1490,25 +1490,22 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
ASSERTF(!(flags & KMC_QCACHE), "Bad KMC_QCACHE (%x)\n", flags);
ASSERT(vmp == NULL);
/* We may be called when there is a non-zero preempt_count or
* interrupts are disabled is which case we must not sleep.
*/
if (current_thread_info()->preempt_count || irqs_disabled())
kmem_flags = KM_NOSLEEP;
might_sleep();
/* Allocate memory for a new cache an initialize it. Unfortunately,
/*
* Allocate memory for a new cache an initialize it. Unfortunately,
* this usually ends up being a large allocation of ~32k because
* we need to allocate enough memory for the worst case number of
* cpus in the magazine, skc_mag[NR_CPUS]. Because of this we
* explicitly pass KM_NODEBUG to suppress the kmem warning */
skc = (spl_kmem_cache_t *)kmem_zalloc(sizeof(*skc),
kmem_flags | KM_NODEBUG);
* explicitly pass KM_NODEBUG to suppress the kmem warning
*/
skc = kmem_zalloc(sizeof(*skc), KM_SLEEP| KM_NODEBUG);
if (skc == NULL)
SRETURN(NULL);
skc->skc_magic = SKC_MAGIC;
skc->skc_name_size = strlen(name) + 1;
skc->skc_name = (char *)kmem_alloc(skc->skc_name_size, kmem_flags);
skc->skc_name = (char *)kmem_alloc(skc->skc_name_size, KM_SLEEP);
if (skc->skc_name == NULL) {
kmem_free(skc, sizeof(*skc));
SRETURN(NULL);