Register correct handlers in nvlist_alloc()

The non-blocking allocation handlers in nvlist_alloc() would be
mistakenly assigned if any flags other than KM_SLEEP were passed.
This meant that nvlists allocated with KM_PUSHPUSH or other KM_*
debug flags were effectively always using atomic allocations.

While these failures were unlikely it could lead to assertions
because KM_PUSHPAGE allocations in particular are guaranteed to
succeed or block.  They must never fail.

Since the existing API does not allow us to pass allocation
flags to the private allocators the cleanest thing to do is to
add a KM_PUSHPAGE allocator.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/spl#249

diff --git a/include/sys/nvpair.h b/include/sys/nvpair.h
index cc399fd16ed738477775f037f5c5dfd947cfecad..c502568a61c9f7fd97d4c7af9e437765e16a37ff 100644 (file)
--- a/include/sys/nvpair.h
+++ b/include/sys/nvpair.h
@@ -144,6 +144,7 @@ extern nv_alloc_t *nv_alloc_nosleep;
 
 #if defined(_KERNEL) && !defined(_BOOT)
 extern nv_alloc_t *nv_alloc_sleep;
+extern nv_alloc_t *nv_alloc_pushpage;
 #endif
 
 int nv_alloc_init(nv_alloc_t *, const nv_alloc_ops_t *, /* args */ ...);

diff --git a/module/nvpair/nvpair.c b/module/nvpair/nvpair.c
index 5c6898446793d5d429b76d592e5a2ce78e827c88..36f4e4dc108f3bd205961ad2f4cd17da502fe7f3 100644 (file)
--- a/module/nvpair/nvpair.c
+++ b/module/nvpair/nvpair.c
@@ -269,12 +269,25 @@ nvlist_nvflag(nvlist_t *nvl)
 int
 nvlist_alloc(nvlist_t **nvlp, uint_t nvflag, int kmflag)
 {
+       nv_alloc_t *nva = nv_alloc_nosleep;
+
 #if defined(_KERNEL) && !defined(_BOOT)
-       return (nvlist_xalloc(nvlp, nvflag,
-           (kmflag == KM_SLEEP ? nv_alloc_sleep : nv_alloc_nosleep)));
-#else
-       return (nvlist_xalloc(nvlp, nvflag, nv_alloc_nosleep));
+       switch (kmflag) {
+       case KM_SLEEP:
+               nva = nv_alloc_sleep;
+               break;
+       case KM_PUSHPAGE:
+               nva = nv_alloc_pushpage;
+               break;
+       case KM_NOSLEEP:
+               nva = nv_alloc_nosleep;
+               break;
+       default:
+               return (EINVAL);
+       }
 #endif
+
+       return (nvlist_xalloc(nvlp, nvflag, nva));
 }
 
 int

diff --git a/module/nvpair/nvpair_alloc_spl.c b/module/nvpair/nvpair_alloc_spl.c
index 63d57a19ab2bbbf9597ed6d280522764367d3a67..be6e8f0a592a606048f1662a7f9c581225a1bba5 100644 (file)
--- a/module/nvpair/nvpair_alloc_spl.c
+++ b/module/nvpair/nvpair_alloc_spl.c
@@ -33,6 +33,12 @@ nv_alloc_sleep_spl(nv_alloc_t *nva, size_t size)
        return (kmem_alloc(size, KM_SLEEP | KM_NODEBUG));
 }
 
+static void *
+nv_alloc_pushpage_spl(nv_alloc_t *nva, size_t size)
+{
+       return (kmem_alloc(size, KM_PUSHPAGE | KM_NODEBUG));
+}
+
 static void *
 nv_alloc_nosleep_spl(nv_alloc_t *nva, size_t size)
 {
@@ -53,6 +59,14 @@ const nv_alloc_ops_t spl_sleep_ops_def = {
        NULL                    /* nv_ao_reset() */
 };
 
+const nv_alloc_ops_t spl_pushpage_ops_def = {
+       NULL,                   /* nv_ao_init() */
+       NULL,                   /* nv_ao_fini() */
+       nv_alloc_pushpage_spl,  /* nv_ao_alloc() */
+       nv_free_spl,            /* nv_ao_free() */
+       NULL                    /* nv_ao_reset() */
+};
+
 const nv_alloc_ops_t spl_nosleep_ops_def = {
        NULL,                   /* nv_ao_init() */
        NULL,                   /* nv_ao_fini() */
@@ -66,10 +80,16 @@ nv_alloc_t nv_alloc_sleep_def = {
        NULL
 };
 
+nv_alloc_t nv_alloc_pushpage_def = {
+       &spl_pushpage_ops_def,
+       NULL
+};
+
 nv_alloc_t nv_alloc_nosleep_def = {
        &spl_nosleep_ops_def,
        NULL
 };
 
 nv_alloc_t *nv_alloc_sleep = &nv_alloc_sleep_def;
+nv_alloc_t *nv_alloc_pushpage = &nv_alloc_pushpage_def;
 nv_alloc_t *nv_alloc_nosleep = &nv_alloc_nosleep_def;