[PATCH v2] nfsd: Avoid strlen conflict in nfsd4_encode_components_esc()

[Nathan Chancellor <nathan@kernel.org>]

There is an error building nfs4xdr.c with CONFIG_SUNRPC_DEBUG_TRACE=y
and CONFIG_FORTIFY_SOURCE=n due to the local variable strlen conflicting
with the function strlen():

  In file included from include/linux/cpumask.h:11,
                   from arch/x86/include/asm/paravirt.h:21,
                   from arch/x86/include/asm/irqflags.h:102,
                   from include/linux/irqflags.h:18,
                   from include/linux/spinlock.h:59,
                   from include/linux/mmzone.h:8,
                   from include/linux/gfp.h:7,
                   from include/linux/slab.h:16,
                   from fs/nfsd/nfs4xdr.c:37:
  fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc':
  include/linux/kernel.h:321:46: error: called object 'strlen' is not a function or function pointer
    321 |                 __trace_puts(_THIS_IP_, str, strlen(str));              \
        |                                              ^~~~~~
  include/linux/kernel.h:265:17: note: in expansion of macro 'trace_puts'
    265 |                 trace_puts(fmt);                        \
        |                 ^~~~~~~~~~
  include/linux/sunrpc/debug.h:34:41: note: in expansion of macro 'trace_printk'
     34 | #  define __sunrpc_printk(fmt, ...)     trace_printk(fmt, ##__VA_ARGS__)
        |                                         ^~~~~~~~~~~~
  include/linux/sunrpc/debug.h:42:17: note: in expansion of macro '__sunrpc_printk'
     42 |                 __sunrpc_printk(fmt, ##__VA_ARGS__);                    \
        |                 ^~~~~~~~~~~~~~~
  include/linux/sunrpc/debug.h:25:9: note: in expansion of macro 'dfprintk'
     25 |         dfprintk(FACILITY, fmt, ##__VA_ARGS__)
        |         ^~~~~~~~
  fs/nfsd/nfs4xdr.c:2646:9: note: in expansion of macro 'dprintk'
   2646 |         dprintk("nfsd4_encode_components(%s)\n", components);
        |         ^~~~~~~
  fs/nfsd/nfs4xdr.c:2643:13: note: declared here
   2643 |         int strlen, count=0;
        |             ^~~~~~

This dprintk() instance is not particularly useful, so just remove it
altogether.

At the same time, rename the strlen local variable to avoid any
potential conflicts with strlen().

Fixes: ec7d8e68ef0e ("sunrpc: add a Kconfig option to redirect dfprintk() output to trace buffer")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Changes in v2:
- Remove dprintk() to remove usage of strlen()
- Rename local strlen variable to avoid potential conflict in the future
- Link to v1: https://patch.msgid.link/20250925-nfsd-fix-trace-printk-strlen-error-v1-1-1360530e4c6b@kernel.org
---
 fs/nfsd/nfs4xdr.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index ea91bad4eee2..9fe8a413f688 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2640,11 +2640,9 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
 	__be32 *p;
 	__be32 pathlen;
 	int pathlen_offset;
-	int strlen, count=0;
+	int str_len, count=0;
 	char *str, *end, *next;
 
-	dprintk("nfsd4_encode_components(%s)\n", components);
-
 	pathlen_offset = xdr->buf->len;
 	p = xdr_reserve_space(xdr, 4);
 	if (!p)
@@ -2670,9 +2668,9 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
 			for (; *end && (*end != sep); end++)
 				/* find sep or end of string */;
 
-		strlen = end - str;
-		if (strlen) {
-			if (xdr_stream_encode_opaque(xdr, str, strlen) < 0)
+		str_len = end - str;
+		if (str_len) {
+			if (xdr_stream_encode_opaque(xdr, str, str_len) < 0)
 				return nfserr_resource;
 			count++;
 		} else

---
base-commit: 3fadfaec904dffab02ebf63dd9c2ae8fa15c6d32
change-id: 20250925-nfsd-fix-trace-printk-strlen-error-2a24413eb186

Best regards,
--  
Nathan Chancellor <nathan@kernel.org>