Changes:
- make sure session memory reservation is released on failure
path.
- use min_t()/min() for more compact code in several places.
- break alloc_init_session into smaller pieces.
- miscellaneous other cleanup.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 211 +++++++++++++++++++++-----------------------------
1 files changed, 89 insertions(+), 122 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ebddcc1..f86476c 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -533,94 +533,6 @@ gen_sessionid(struct nfsd4_session *ses)
*/
#define NFSD_MIN_HDR_SEQ_SZ (24 + 12 + 44)
-/*
- * Give the client the number of ca_maxresponsesize_cached slots it
- * requests, of size bounded by NFSD_SLOT_CACHE_SIZE,
- * NFSD_MAX_MEM_PER_SESSION, and nfsd_drc_max_mem. Do not allow more
- * than NFSD_MAX_SLOTS_PER_SESSION.
- *
- * If we run out of reserved DRC memory we should (up to a point)
- * re-negotiate active sessions and reduce their slot usage to make
- * rooom for new connections. For now we just fail the create session.
- */
-static int set_forechannel_drc_size(struct nfsd4_channel_attrs *fchan)
-{
- int mem, size = fchan->maxresp_cached;
-
- if (fchan->maxreqs < 1)
- return nfserr_inval;
-
- if (size < NFSD_MIN_HDR_SEQ_SZ)
- size = NFSD_MIN_HDR_SEQ_SZ;
- size -= NFSD_MIN_HDR_SEQ_SZ;
- if (size > NFSD_SLOT_CACHE_SIZE)
- size = NFSD_SLOT_CACHE_SIZE;
-
- /* bound the maxreqs by NFSD_MAX_MEM_PER_SESSION */
- mem = fchan->maxreqs * size;
- if (mem > NFSD_MAX_MEM_PER_SESSION) {
- fchan->maxreqs = NFSD_MAX_MEM_PER_SESSION / size;
- if (fchan->maxreqs > NFSD_MAX_SLOTS_PER_SESSION)
- fchan->maxreqs = NFSD_MAX_SLOTS_PER_SESSION;
- mem = fchan->maxreqs * size;
- }
-
- spin_lock(&nfsd_drc_lock);
- /* bound the total session drc memory ussage */
- if (mem + nfsd_drc_mem_used > nfsd_drc_max_mem) {
- fchan->maxreqs = (nfsd_drc_max_mem - nfsd_drc_mem_used) / size;
- mem = fchan->maxreqs * size;
- }
- nfsd_drc_mem_used += mem;
- spin_unlock(&nfsd_drc_lock);
-
- if (fchan->maxreqs == 0)
- return nfserr_jukebox;
-
- fchan->maxresp_cached = size + NFSD_MIN_HDR_SEQ_SZ;
- return 0;
-}
-
-/*
- * fchan holds the client values on input, and the server values on output
- * sv_max_mesg is the maximum payload plus one page for overhead.
- */
-static int init_forechannel_attrs(struct svc_rqst *rqstp,
- struct nfsd4_channel_attrs *session_fchan,
- struct nfsd4_channel_attrs *fchan)
-{
- int status = 0;
- __u32 maxcount = nfsd_serv->sv_max_mesg;
-
- /* headerpadsz set to zero in encode routine */
-
- /* Use the client's max request and max response size if possible */
- if (fchan->maxreq_sz > maxcount)
- fchan->maxreq_sz = maxcount;
- session_fchan->maxreq_sz = fchan->maxreq_sz;
-
- if (fchan->maxresp_sz > maxcount)
- fchan->maxresp_sz = maxcount;
- session_fchan->maxresp_sz = fchan->maxresp_sz;
-
- /* Use the client's maxops if possible */
- if (fchan->maxops > NFSD_MAX_OPS_PER_COMPOUND)
- fchan->maxops = NFSD_MAX_OPS_PER_COMPOUND;
- session_fchan->maxops = fchan->maxops;
-
- /* FIXME: Error means no more DRC pages so the server should
- * recover pages from existing sessions. For now fail session
- * creation.
- */
- status = set_forechannel_drc_size(fchan);
-
- session_fchan->maxresp_cached = fchan->maxresp_cached;
- session_fchan->maxreqs = fchan->maxreqs;
-
- dprintk("%s status %d\n", __func__, status);
- return status;
-}
-
static void
free_session_slots(struct nfsd4_session *ses)
{
@@ -639,63 +551,118 @@ static inline int slot_bytes(struct nfsd4_channel_attrs *ca)
return ca->maxresp_cached - NFSD_MIN_HDR_SEQ_SZ;
}
-static __be32 alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp, struct nfsd4_create_session *cses)
+static int nfsd4_sanitize_slot_size(u32 size)
{
- struct nfsd4_session *new, tmp;
- struct nfsd4_slot *sp;
- int idx, slotsize, cachesize, i;
- int status;
+ size -= NFSD_MIN_HDR_SEQ_SZ; /* We don't cache the rpc header */
+ size = min_t(u32, size, NFSD_SLOT_CACHE_SIZE);
- memset(&tmp, 0, sizeof(tmp));
+ return size;
+}
- /* FIXME: For now, we just accept the client back channel attributes. */
- tmp.se_bchannel = cses->back_channel;
- status = init_forechannel_attrs(rqstp, &tmp.se_fchannel,
- &cses->fore_channel);
- if (status)
- goto out;
+/*
+ * XXX: If we run out of reserved DRC memory we could (up to a point)
+ * re-negotiate active sessions and reduce their slot usage to make
+ * rooom for new connections. For now we just fail the create session.
+ */
+static int nfsd4_get_drc_mem(int slotsize, u32 num)
+{
+ int avail;
- BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot *)
- + sizeof(struct nfsd4_session) > PAGE_SIZE);
+ num = min_t(u32, num, NFSD_MAX_SLOTS_PER_SESSION);
- status = nfserr_jukebox;
- /* allocate struct nfsd4_session and slot table pointers in one piece */
- slotsize = tmp.se_fchannel.maxreqs * sizeof(struct nfsd4_slot *);
- new = kzalloc(sizeof(*new) + slotsize, GFP_KERNEL);
- if (!new)
- goto out;
+ spin_lock(&nfsd_drc_lock);
+ avail = min_t(int, NFSD_MAX_MEM_PER_SESSION,
+ nfsd_drc_max_mem - nfsd_drc_mem_used);
+ num = min_t(int, num, avail / slotsize);
+ nfsd_drc_mem_used += num * slotsize;
+ spin_unlock(&nfsd_drc_lock);
+
+ return num;
+}
+
+static void nfsd4_put_drc_mem(int slotsize, int num)
+{
+ spin_lock(&nfsd_drc_lock);
+ nfsd_drc_mem_used -= slotsize * num;
+ spin_unlock(&nfsd_drc_lock);
+}
+
+static struct nfsd4_session *alloc_session(int slotsize, int numslots)
+{
+ struct nfsd4_session *new;
+ int mem, i;
- memcpy(new, &tmp, sizeof(*new));
+ BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot *)
+ + sizeof(struct nfsd4_session) > PAGE_SIZE);
+ mem = numslots * sizeof(struct nfsd4_slot *);
+ new = kzalloc(sizeof(*new) + mem, GFP_KERNEL);
+ if (!new)
+ return NULL;
/* allocate each struct nfsd4_slot and data cache in one piece */
- cachesize = slot_bytes(&new->se_fchannel);
- for (i = 0; i < new->se_fchannel.maxreqs; i++) {
- sp = kzalloc(sizeof(*sp) + cachesize, GFP_KERNEL);
- if (!sp)
+ for (i = 0; i < numslots; i++) {
+ mem = sizeof(struct nfsd4_slot) + slotsize;
+ new->se_slots[i] = kzalloc(mem, GFP_KERNEL);
+ if (!new->se_slots[i])
goto out_free;
- new->se_slots[i] = sp;
}
+ return new;
+out_free:
+ while (i--)
+ kfree(new->se_slots[i]);
+ kfree(new);
+ return NULL;
+}
+
+static void init_forechannel_attrs(struct nfsd4_channel_attrs *new, struct nfsd4_channel_attrs *req, int numslots, int slotsize)
+{
+ u32 maxrpc = nfsd_serv->sv_max_mesg;
+
+ new->maxreqs = numslots;
+ new->maxresp_cached = slotsize + NFSD_MIN_HDR_SEQ_SZ;
+ new->maxreq_sz = min_t(u32, req->maxreq_sz, maxrpc);
+ new->maxresp_sz = min_t(u32, req->maxresp_sz, maxrpc);
+ new->maxops = min_t(u32, req->maxops, NFSD_MAX_OPS_PER_COMPOUND);
+}
+
+static __be32 alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp, struct nfsd4_create_session *cses)
+{
+ struct nfsd4_session *new;
+ struct nfsd4_channel_attrs *fchan = &cses->fore_channel;
+ int numslots, slotsize;
+ int idx;
+
+ /*
+ * Note decreasing slot size below client's request may
+ * make it difficult for client to function correctly, whereas
+ * decreasing the number of slots will (just?) affect
+ * performance. When short on memory we therefore prefer to
+ * decrease number of slots instead of their size.
+ */
+ slotsize = nfsd4_sanitize_slot_size(fchan->maxresp_cached);
+ numslots = nfsd4_get_drc_mem(slotsize, fchan->maxreqs);
+
+ new = alloc_session(slotsize, numslots);
+ if (!new) {
+ nfsd4_put_drc_mem(slotsize, fchan->maxreqs);
+ return nfserr_jukebox;
+ }
+ init_forechannel_attrs(&new->se_fchannel, fchan, numslots, slotsize);
new->se_client = clp;
gen_sessionid(new);
- idx = hash_sessionid(&new->se_sessionid);
memcpy(clp->cl_sessionid.data, new->se_sessionid.data,
NFS4_MAX_SESSIONID_LEN);
new->se_flags = cses->flags;
kref_init(&new->se_ref);
+ idx = hash_sessionid(&new->se_sessionid);
spin_lock(&client_lock);
list_add(&new->se_hash, &sessionid_hashtbl[idx]);
list_add(&new->se_perclnt, &clp->cl_sessions);
spin_unlock(&client_lock);
- status = nfs_ok;
-out:
- return status;
-out_free:
- free_session_slots(new);
- kfree(new);
- goto out;
+ return nfs_ok;
}
/* caller must hold client_lock */
--
1.7.0.4
--
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