nfsd: shrink st_access_bmap and st_deny_bmap

We never use anything above bit #3, so an unsigned long for each is
wasteful. Shrink them to a char each, and add some WARN_ON_ONCE calls if
we try to set or clear bits that would go outside those sizes.

Note too that because atomic bitops work on unsigned longs, we have to
abandon their use here. That shouldn't be a problem though since we
don't really care about the atomicity in this code anyway. Using them
was just a convenient way to flip bits.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c02bad6d7e90c6af15d360eb5580c91fe92c03b2..f7f11631c26cebf597adcb116e485ec56fe83796 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -721,42 +721,58 @@ test_share(struct nfs4_ol_stateid *stp, struct nfsd4_open *open) {
 static inline void
 set_access(u32 access, struct nfs4_ol_stateid *stp)
 {
-       __set_bit(access, &stp->st_access_bmap);
+       unsigned char mask = 1 << access;
+
+       WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
+       stp->st_access_bmap |= mask;
 }
 
 /* clear share access for a given stateid */
 static inline void
 clear_access(u32 access, struct nfs4_ol_stateid *stp)
 {
-       __clear_bit(access, &stp->st_access_bmap);
+       unsigned char mask = 1 << access;
+
+       WARN_ON_ONCE(access > NFS4_SHARE_ACCESS_BOTH);
+       stp->st_access_bmap &= ~mask;
 }
 
 /* test whether a given stateid has access */
 static inline bool
 test_access(u32 access, struct nfs4_ol_stateid *stp)
 {
-       return test_bit(access, &stp->st_access_bmap);
+       unsigned char mask = 1 << access;
+
+       return (bool)(stp->st_access_bmap & mask);
 }
 
 /* set share deny for a given stateid */
 static inline void
-set_deny(u32 access, struct nfs4_ol_stateid *stp)
+set_deny(u32 deny, struct nfs4_ol_stateid *stp)
 {
-       __set_bit(access, &stp->st_deny_bmap);
+       unsigned char mask = 1 << deny;
+
+       WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
+       stp->st_deny_bmap |= mask;
 }
 
 /* clear share deny for a given stateid */
 static inline void
-clear_deny(u32 access, struct nfs4_ol_stateid *stp)
+clear_deny(u32 deny, struct nfs4_ol_stateid *stp)
 {
-       __clear_bit(access, &stp->st_deny_bmap);
+       unsigned char mask = 1 << deny;
+
+       WARN_ON_ONCE(deny > NFS4_SHARE_DENY_BOTH);
+       stp->st_deny_bmap &= ~mask;
 }
 
 /* test whether a given stateid is denying specific access */
 static inline bool
-test_deny(u32 access, struct nfs4_ol_stateid *stp)
+test_deny(u32 deny, struct nfs4_ol_stateid *stp)
 {
-       return test_bit(access, &stp->st_deny_bmap);
+       unsigned char mask = 1 << deny;
+
+       return (bool)(stp->st_deny_bmap & mask);
 }
 
 static int nfs4_access_to_omode(u32 access)
@@ -4282,12 +4298,12 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
                goto out; 
        status = nfserr_inval;
        if (!test_access(od->od_share_access, stp)) {
-               dprintk("NFSD: access not a subset current bitmap: 0x%lx, input access=%08x\n",
+               dprintk("NFSD: access not a subset of current bitmap: 0x%hhx, input access=%08x\n",
                        stp->st_access_bmap, od->od_share_access);
                goto out;
        }
        if (!test_deny(od->od_share_deny, stp)) {
-               dprintk("NFSD:deny not a subset current bitmap: 0x%lx, input deny=%08x\n",
+               dprintk("NFSD: deny not a subset of current bitmap: 0x%hhx, input deny=%08x\n",
                        stp->st_deny_bmap, od->od_share_deny);
                goto out;
        }

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 9f1159d5de5621c2ef54f9716134c013e8b4d721..72aee4b4f1aea7ba3c6119ce12d837aa1c31bc71 100644 (file)
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -406,8 +406,8 @@ struct nfs4_ol_stateid {
        struct list_head              st_locks;
        struct nfs4_stateowner      * st_stateowner;
        struct nfs4_file            * st_file;
-       unsigned long                 st_access_bmap;
-       unsigned long                 st_deny_bmap;
+       unsigned char                 st_access_bmap;
+       unsigned char                 st_deny_bmap;
        struct nfs4_ol_stateid         * st_openstp;
 };