NFSD: Fix frame size warning in svc_export_parse()

[ Upstream commit 6939ace1f22681fface7841cdbf34d3204cc94b5 ]

fs/nfsd/export.c: In function 'svc_export_parse':
fs/nfsd/export.c:737:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
    737 | }

On my systems, svc_export_parse() has a stack frame of over 800
bytes, not 1040, but nonetheless, it could do with some reduction.

When a struct svc_export is on the stack, it's a temporary structure
used as an argument, and not visible as an actual exported FS. No
need to reserve space for export_stats in such cases.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310012359.YEw5IrK6-lkp@intel.com/
Cc: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Stable-dep-of: 4b14885411f7 ("nfsd: make all of the nfsd stats per-network namespace")
[ cel: adjusted to apply to v5.10.y ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 7c863f2c21e0c6acc5d0cdfb17a4ec5f816d44b6..617a5b6ae6c38e3f5f7c5eaa31b0c8ade05a90d5 100644 (file)
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -339,12 +339,16 @@ static int export_stats_init(struct export_stats *stats)
 
 static void export_stats_reset(struct export_stats *stats)
 {
-       nfsd_percpu_counters_reset(stats->counter, EXP_STATS_COUNTERS_NUM);
+       if (stats)
+               nfsd_percpu_counters_reset(stats->counter,
+                                          EXP_STATS_COUNTERS_NUM);
 }
 
 static void export_stats_destroy(struct export_stats *stats)
 {
-       nfsd_percpu_counters_destroy(stats->counter, EXP_STATS_COUNTERS_NUM);
+       if (stats)
+               nfsd_percpu_counters_destroy(stats->counter,
+                                            EXP_STATS_COUNTERS_NUM);
 }
 
 static void svc_export_put(struct kref *ref)
@@ -353,7 +357,8 @@ static void svc_export_put(struct kref *ref)
        path_put(&exp->ex_path);
        auth_domain_put(exp->ex_client);
        nfsd4_fslocs_free(&exp->ex_fslocs);
-       export_stats_destroy(&exp->ex_stats);
+       export_stats_destroy(exp->ex_stats);
+       kfree(exp->ex_stats);
        kfree(exp->ex_uuid);
        kfree_rcu(exp, ex_rcu);
 }
@@ -738,13 +743,15 @@ static int svc_export_show(struct seq_file *m,
        seq_putc(m, '\t');
        seq_escape(m, exp->ex_client->name, " \t\n\\");
        if (export_stats) {
-               seq_printf(m, "\t%lld\n", exp->ex_stats.start_time);
+               struct percpu_counter *counter = exp->ex_stats->counter;
+
+               seq_printf(m, "\t%lld\n", exp->ex_stats->start_time);
                seq_printf(m, "\tfh_stale: %lld\n",
-                          percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_FH_STALE]));
+                          percpu_counter_sum_positive(&counter[EXP_STATS_FH_STALE]));
                seq_printf(m, "\tio_read: %lld\n",
-                          percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_IO_READ]));
+                          percpu_counter_sum_positive(&counter[EXP_STATS_IO_READ]));
                seq_printf(m, "\tio_write: %lld\n",
-                          percpu_counter_sum_positive(&exp->ex_stats.counter[EXP_STATS_IO_WRITE]));
+                          percpu_counter_sum_positive(&counter[EXP_STATS_IO_WRITE]));
                seq_putc(m, '\n');
                return 0;
        }
@@ -790,7 +797,7 @@ static void svc_export_init(struct cache_head *cnew, struct cache_head *citem)
        new->ex_layout_types = 0;
        new->ex_uuid = NULL;
        new->cd = item->cd;
-       export_stats_reset(&new->ex_stats);
+       export_stats_reset(new->ex_stats);
 }
 
 static void export_update(struct cache_head *cnew, struct cache_head *citem)
@@ -826,7 +833,14 @@ static struct cache_head *svc_export_alloc(void)
        if (!i)
                return NULL;
 
-       if (export_stats_init(&i->ex_stats)) {
+       i->ex_stats = kmalloc(sizeof(*(i->ex_stats)), GFP_KERNEL);
+       if (!i->ex_stats) {
+               kfree(i);
+               return NULL;
+       }
+
+       if (export_stats_init(i->ex_stats)) {
+               kfree(i->ex_stats);
                kfree(i);
                return NULL;
        }

diff --git a/fs/nfsd/export.h b/fs/nfsd/export.h
index d03f7f6a8642d354f03d33306b2344996f57375f..f73e23bb24a1eacd18ccd98bfd452a7597e139c2 100644 (file)
--- a/fs/nfsd/export.h
+++ b/fs/nfsd/export.h
@@ -64,10 +64,10 @@ struct svc_export {
        struct cache_head       h;
        struct auth_domain *    ex_client;
        int                     ex_flags;
+       int                     ex_fsid;
        struct path             ex_path;
        kuid_t                  ex_anon_uid;
        kgid_t                  ex_anon_gid;
-       int                     ex_fsid;
        unsigned char *         ex_uuid; /* 16 byte fsid */
        struct nfsd4_fs_locations ex_fslocs;
        uint32_t                ex_nflavors;
@@ -76,7 +76,7 @@ struct svc_export {
        struct nfsd4_deviceid_map *ex_devid_map;
        struct cache_detail     *cd;
        struct rcu_head         ex_rcu;
-       struct export_stats     ex_stats;
+       struct export_stats     *ex_stats;
 };
 
 /* an "export key" (expkey) maps a filehandlefragement to an

diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
index c3abe1830da55c017a926abb5df8c7165d9bfed7..ac58c4b2ab708db67cf72bc62c3d46ca35c4f485 100644 (file)
--- a/fs/nfsd/stats.h
+++ b/fs/nfsd/stats.h
@@ -60,22 +60,22 @@ static inline void nfsd_stats_rc_nocache_inc(void)
 static inline void nfsd_stats_fh_stale_inc(struct svc_export *exp)
 {
        percpu_counter_inc(&nfsdstats.counter[NFSD_STATS_FH_STALE]);
-       if (exp)
-               percpu_counter_inc(&exp->ex_stats.counter[EXP_STATS_FH_STALE]);
+       if (exp && exp->ex_stats)
+               percpu_counter_inc(&exp->ex_stats->counter[EXP_STATS_FH_STALE]);
 }
 
 static inline void nfsd_stats_io_read_add(struct svc_export *exp, s64 amount)
 {
        percpu_counter_add(&nfsdstats.counter[NFSD_STATS_IO_READ], amount);
-       if (exp)
-               percpu_counter_add(&exp->ex_stats.counter[EXP_STATS_IO_READ], amount);
+       if (exp && exp->ex_stats)
+               percpu_counter_add(&exp->ex_stats->counter[EXP_STATS_IO_READ], amount);
 }
 
 static inline void nfsd_stats_io_write_add(struct svc_export *exp, s64 amount)
 {
        percpu_counter_add(&nfsdstats.counter[NFSD_STATS_IO_WRITE], amount);
-       if (exp)
-               percpu_counter_add(&exp->ex_stats.counter[EXP_STATS_IO_WRITE], amount);
+       if (exp && exp->ex_stats)
+               percpu_counter_add(&exp->ex_stats->counter[EXP_STATS_IO_WRITE], amount);
 }
 
 static inline void nfsd_stats_payload_misses_inc(struct nfsd_net *nn)