linux-kernel - [PATCH v1 1/1] cifs: Get rid of unneeded conditional in the smb2_get_aead

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Message-Id: <20230120120857.60444-1-andriy.shevchenko@linux.intel.com>
Date:   Fri, 20 Jan 2023 14:08:57 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Steve French <stfrench@...rosoft.com>, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org, linux-kernel@...r.kernel.org
Cc:     Steve French <sfrench@...ba.org>, Paulo Alcantara <pc@....nz>,
        Ronnie Sahlberg <lsahlber@...hat.com>,
        Shyam Prasad N <sprasad@...rosoft.com>,
        Tom Talpey <tom@...pey.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1 1/1] cifs: Get rid of unneeded conditional in the smb2_get_aead_req()

In the smb2_get_aead_req() the skip variable is used only for
the very first iteration of the two nested loops, which means
it's basically in invariant to those loops. Hence, instead of
using conditional on each iteration, unconditionally assing
the 'skip' variable before the loops and at the end of the
inner loop.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 fs/cifs/smb2ops.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 519e6124d73d..7fcb79ce6a94 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4280,6 +4280,12 @@ static void *smb2_get_aead_req(struct crypto_aead *tfm, const struct smb_rqst *r
 	sg_init_table(*sgl, num_sgs);
 	sg = *sgl;
 
+	/*
+	 * The first rqst has a transform header where the
+	 * first 20 bytes are not part of the encrypted blob.
+	 */
+	skip = 20;
+
 	/* Assumes the first rqst has a transform header as the first iov.
 	 * I.e.
 	 * rqst[0].rq_iov[0]  is transform header
@@ -4287,17 +4293,15 @@ static void *smb2_get_aead_req(struct crypto_aead *tfm, const struct smb_rqst *r
 	 * rqst[1+].rq_iov[0+] data to be encrypted/decrypted
 	 */
 	for (i = 0; i < num_rqst; i++) {
-		/*
-		 * The first rqst has a transform header where the
-		 * first 20 bytes are not part of the encrypted blob.
-		 */
 		for (j = 0; j < rqst[i].rq_nvec; j++) {
 			struct kvec *iov = &rqst[i].rq_iov[j];
 
-			skip = (i == 0) && (j == 0) ? 20 : 0;
 			addr = (unsigned long)iov->iov_base + skip;
 			len = iov->iov_len - skip;
 			sg = cifs_sg_set_buf(sg, (void *)addr, len);
+
+			/* See the above comment on the 'skip' assignment */
+			skip = 0;
 		}
 		for (j = 0; j < rqst[i].rq_npages; j++) {
 			rqst_page_get_length(&rqst[i], j, &len, &off);
-- 
2.39.0