mtd: remove extra retlen assignment

MTD functions always assign the 'retlen' argument to 0 at the very
beginning - the callers do not have to do this.

I used the following semantic patch to find these places:

@@
identifier retlen;
expression a, b, c, d, e;
constant C;
type T;
@@
(
- retlen = C;
|
T
-retlen = C
+ retlen
;
)

... when != retlen
    when exists

(
mtd_read(a, b, c, &retlen, d)
|
mtd_write(a, b, c, &retlen, d)
|
mtd_panic_write(a, b, c, &retlen, d)
|
mtd_point(a, b, c, &retlen, d, e)
|
mtd_read_fact_prot_reg(a, b, c, &retlen, d)
|
mtd_write_user_prot_reg(a, b, c, &retlen, d)
|
mtd_read_user_prot_reg(a, b, c, &retlen, d)
|
mtd_writev(a, b, c, d, &retlen)
)

I ran it twice, because there were cases of double zero assigments
in mtd tests. Then I went through the patch to verify that spatch
did not find any false positives.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

7 files changed, 22 insertions, 33 deletions

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 15a3f6224be4..83b0c82e9c94 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -189,7 +189,7 @@ static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
 {
         struct mtd_file_info *mfi = file->private_data;
         struct mtd_info *mtd = mfi->mtd;
-        size_t retlen=0;
+        size_t retlen;
         size_t total_retlen=0;
         int ret=0;
         int len;
diff --git a/drivers/mtd/tests/mtd_pagetest.c b/drivers/mtd/tests/mtd_pagetest.c
index 8024eaf4c1ac..252ddb092fb2 100644
--- a/drivers/mtd/tests/mtd_pagetest.c
+++ b/drivers/mtd/tests/mtd_pagetest.c
@@ -95,7 +95,7 @@ static int erase_eraseblock(int ebnum)
 static int write_eraseblock(int ebnum)
 {
         int err = 0;
-        size_t written = 0;
+        size_t written;
         loff_t addr = ebnum * mtd->erasesize;
 
         set_random_data(writebuf, mtd->erasesize);
@@ -111,7 +111,7 @@ static int write_eraseblock(int ebnum)
 static int verify_eraseblock(int ebnum)
 {
         uint32_t j;
-        size_t read = 0;
+        size_t read;
         int err = 0, i;
         loff_t addr0, addrn;
         loff_t addr = ebnum * mtd->erasesize;
@@ -144,7 +144,6 @@ static int verify_eraseblock(int ebnum)
                         return err;
                 }
                 memset(twopages, 0, bufsize);
-                read = 0;
                 err = mtd_read(mtd, addr, bufsize, &read, twopages);
                 if (mtd_is_bitflip(err))
                         err = 0;
@@ -180,7 +179,6 @@ static int verify_eraseblock(int ebnum)
                         return err;
                 }
                 memset(twopages, 0, bufsize);
-                read = 0;
                 err = mtd_read(mtd, addr, bufsize, &read, twopages);
                 if (mtd_is_bitflip(err))
                         err = 0;
@@ -203,7 +201,7 @@ static int verify_eraseblock(int ebnum)
 
 static int crosstest(void)
 {
-        size_t read = 0;
+        size_t read;
         int err = 0, i;
         loff_t addr, addr0, addrn;
         unsigned char *pp1, *pp2, *pp3, *pp4;
@@ -228,7 +226,6 @@ static int crosstest(void)
                 addrn -= mtd->erasesize;
 
         /* Read 2nd-to-last page to pp1 */
-        read = 0;
         addr = addrn - pgsize - pgsize;
         err = mtd_read(mtd, addr, pgsize, &read, pp1);
         if (mtd_is_bitflip(err))
@@ -241,7 +238,6 @@ static int crosstest(void)
         }
 
         /* Read 3rd-to-last page to pp1 */
-        read = 0;
         addr = addrn - pgsize - pgsize - pgsize;
         err = mtd_read(mtd, addr, pgsize, &read, pp1);
         if (mtd_is_bitflip(err))
@@ -254,7 +250,6 @@ static int crosstest(void)
         }
 
         /* Read first page to pp2 */
-        read = 0;
         addr = addr0;
         printk(PRINT_PREF "reading page at %#llx\n", (long long)addr);
         err = mtd_read(mtd, addr, pgsize, &read, pp2);
@@ -268,7 +263,6 @@ static int crosstest(void)
         }
 
         /* Read last page to pp3 */
-        read = 0;
         addr = addrn - pgsize;
         printk(PRINT_PREF "reading page at %#llx\n", (long long)addr);
         err = mtd_read(mtd, addr, pgsize, &read, pp3);
@@ -282,7 +276,6 @@ static int crosstest(void)
         }
 
         /* Read first page again to pp4 */
-        read = 0;
         addr = addr0;
         printk(PRINT_PREF "reading page at %#llx\n", (long long)addr);
         err = mtd_read(mtd, addr, pgsize, &read, pp4);
@@ -309,7 +302,7 @@ static int crosstest(void)
 
 static int erasecrosstest(void)
 {
-        size_t read = 0, written = 0;
+        size_t read, written;
         int err = 0, i, ebnum, ebnum2;
         loff_t addr0;
         char *readbuf = twopages;
@@ -405,7 +398,7 @@ static int erasecrosstest(void)
 
 static int erasetest(void)
 {
-        size_t read = 0, written = 0;
+        size_t read, written;
         int err = 0, i, ebnum, ok = 1;
         loff_t addr0;
 
diff --git a/drivers/mtd/tests/mtd_readtest.c b/drivers/mtd/tests/mtd_readtest.c
index ad5fd0df86ee..4228eb4e54c7 100644
--- a/drivers/mtd/tests/mtd_readtest.c
+++ b/drivers/mtd/tests/mtd_readtest.c
@@ -44,7 +44,7 @@ static int pgcnt;
 
 static int read_eraseblock_by_page(int ebnum)
 {
-        size_t read = 0;
+        size_t read;
         int i, ret, err = 0;
         loff_t addr = ebnum * mtd->erasesize;
         void *buf = iobuf;
diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index ecb287847505..4d2ed5c0807d 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -139,7 +139,7 @@ static int erase_whole_device(void)
 
 static int write_eraseblock(int ebnum)
 {
-        size_t written = 0;
+        size_t written;
         int err = 0;
         loff_t addr = ebnum * mtd->erasesize;
 
@@ -155,7 +155,7 @@ static int write_eraseblock(int ebnum)
 
 static int write_eraseblock_by_page(int ebnum)
 {
-        size_t written = 0;
+        size_t written;
         int i, err = 0;
         loff_t addr = ebnum * mtd->erasesize;
         void *buf = iobuf;
@@ -178,7 +178,7 @@ static int write_eraseblock_by_page(int ebnum)
 
 static int write_eraseblock_by_2pages(int ebnum)
 {
-        size_t written = 0, sz = pgsize * 2;
+        size_t written, sz = pgsize * 2;
         int i, n = pgcnt / 2, err = 0;
         loff_t addr = ebnum * mtd->erasesize;
         void *buf = iobuf;
@@ -210,7 +210,7 @@ static int write_eraseblock_by_2pages(int ebnum)
 
 static int read_eraseblock(int ebnum)
 {
-        size_t read = 0;
+        size_t read;
         int err = 0;
         loff_t addr = ebnum * mtd->erasesize;
 
@@ -229,7 +229,7 @@ static int read_eraseblock(int ebnum)
 
 static int read_eraseblock_by_page(int ebnum)
 {
-        size_t read = 0;
+        size_t read;
         int i, err = 0;
         loff_t addr = ebnum * mtd->erasesize;
         void *buf = iobuf;
@@ -255,7 +255,7 @@ static int read_eraseblock_by_page(int ebnum)
 
 static int read_eraseblock_by_2pages(int ebnum)
 {
-        size_t read = 0, sz = pgsize * 2;
+        size_t read, sz = pgsize * 2;
         int i, n = pgcnt / 2, err = 0;
         loff_t addr = ebnum * mtd->erasesize;
         void *buf = iobuf;
diff --git a/drivers/mtd/tests/mtd_stresstest.c b/drivers/mtd/tests/mtd_stresstest.c
index 4789c0ee3e9a..399aa2bf220d 100644
--- a/drivers/mtd/tests/mtd_stresstest.c
+++ b/drivers/mtd/tests/mtd_stresstest.c
@@ -140,7 +140,7 @@ static int is_block_bad(int ebnum)
 
 static int do_read(void)
 {
-        size_t read = 0;
+        size_t read;
         int eb = rand_eb();
         int offs = rand_offs();
         int len = rand_len(offs), err;
@@ -169,7 +169,7 @@ static int do_read(void)
 static int do_write(void)
 {
         int eb = rand_eb(), offs, err, len;
-        size_t written = 0;
+        size_t written;
         loff_t addr;
 
         offs = offsets[eb];
diff --git a/drivers/mtd/tests/mtd_subpagetest.c b/drivers/mtd/tests/mtd_subpagetest.c
index 4b873d49fe6a..9667bf535282 100644
--- a/drivers/mtd/tests/mtd_subpagetest.c
+++ b/drivers/mtd/tests/mtd_subpagetest.c
@@ -115,7 +115,7 @@ static int erase_whole_device(void)
 
 static int write_eraseblock(int ebnum)
 {
-        size_t written = 0;
+        size_t written;
         int err = 0;
         loff_t addr = ebnum * mtd->erasesize;
 
@@ -150,7 +150,7 @@ static int write_eraseblock(int ebnum)
 
 static int write_eraseblock2(int ebnum)
 {
-        size_t written = 0;
+        size_t written;
         int err = 0, k;
         loff_t addr = ebnum * mtd->erasesize;
 
@@ -189,13 +189,12 @@ static void print_subpage(unsigned char *p)
 
 static int verify_eraseblock(int ebnum)
 {
-        size_t read = 0;
+        size_t read;
         int err = 0;
         loff_t addr = ebnum * mtd->erasesize;
 
         set_random_data(writebuf, subpgsize);
         clear_data(readbuf, subpgsize);
-        read = 0;
         err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
         if (unlikely(err || read != subpgsize)) {
                 if (mtd_is_bitflip(err) && read == subpgsize) {
@@ -223,7 +222,6 @@ static int verify_eraseblock(int ebnum)
 
         set_random_data(writebuf, subpgsize);
         clear_data(readbuf, subpgsize);
-        read = 0;
         err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
         if (unlikely(err || read != subpgsize)) {
                 if (mtd_is_bitflip(err) && read == subpgsize) {
@@ -252,7 +250,7 @@ static int verify_eraseblock(int ebnum)
 
 static int verify_eraseblock2(int ebnum)
 {
-        size_t read = 0;
+        size_t read;
         int err = 0, k;
         loff_t addr = ebnum * mtd->erasesize;
 
@@ -261,7 +259,6 @@ static int verify_eraseblock2(int ebnum)
                         break;
                 set_random_data(writebuf, subpgsize * k);
                 clear_data(readbuf, subpgsize * k);
-                read = 0;
                 err = mtd_read(mtd, addr, subpgsize * k, &read, readbuf);
                 if (unlikely(err || read != subpgsize * k)) {
                         if (mtd_is_bitflip(err) && read == subpgsize * k) {
@@ -288,14 +285,13 @@ static int verify_eraseblock2(int ebnum)
 static int verify_eraseblock_ff(int ebnum)
 {
         uint32_t j;
-        size_t read = 0;
+        size_t read;
         int err = 0;
         loff_t addr = ebnum * mtd->erasesize;
 
         memset(writebuf, 0xff, subpgsize);
         for (j = 0; j < mtd->erasesize / subpgsize; ++j) {
                 clear_data(readbuf, subpgsize);
-                read = 0;
                 err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
                 if (unlikely(err || read != subpgsize)) {
                         if (mtd_is_bitflip(err) && read == subpgsize) {
diff --git a/drivers/mtd/tests/mtd_torturetest.c b/drivers/mtd/tests/mtd_torturetest.c
index 30c4ed9855ec..557105f2ead3 100644
--- a/drivers/mtd/tests/mtd_torturetest.c
+++ b/drivers/mtd/tests/mtd_torturetest.c
@@ -127,7 +127,7 @@ static inline int erase_eraseblock(int ebnum)
 static inline int check_eraseblock(int ebnum, unsigned char *buf)
 {
         int err, retries = 0;
-        size_t read = 0;
+        size_t read;
         loff_t addr = ebnum * mtd->erasesize;
         size_t len = mtd->erasesize;
 
@@ -181,7 +181,7 @@ retry:
 static inline int write_pattern(int ebnum, void *buf)
 {
         int err;
-        size_t written = 0;
+        size_t written;
         loff_t addr = ebnum * mtd->erasesize;
         size_t len = mtd->erasesize;