[PATCH 1/2] libfile: Simplify read_full()

[PATCH 1/2] libfile: Simplify read_full()

[Andrey Smirnov]

We can figure out the amount of written data by substracting 'insize'
from 'size' so there is no need to keep a separate counter for that.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 lib/libfile.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/libfile.c b/lib/libfile.c
index eb12d158d..814cd9c2c 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -80,20 +80,18 @@ int read_full(int fd, void *buf, size_t size)
 {
 	size_t insize = size;
 	int now;
-	int total = 0;
 
 	while (size) {
 		now = read(fd, buf, size);
 		if (now == 0)
-			return total;
+			break;
 		if (now < 0)
 			return now;
-		total += now;
 		size -= now;
 		buf += now;
 	}
 
-	return insize;
+	return insize - size;
 }
 EXPORT_SYMBOL(read_full);
 
-- 
2.21.0


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[PATCH 2/2] libfile: Do not return 0 from write_full()

[Andrey Smirnov]

None of the callers of write_full() expect a zero return value. Given
how the documentation explicitly states that either all of the buffer
is going to be written out or an error generated, treat 0 retrun from
write() as a error, set errno to ENOSPC and return -1.

Same logic applies to pwrite_full() as well, so make the change there
while at it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 lib/libfile.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/libfile.c b/lib/libfile.c
index 814cd9c2c..b42753c2b 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -36,7 +36,11 @@ int pwrite_full(int fd, const void *buf, size_t size, loff_t offset)
 
 	while (size) {
 		now = pwrite(fd, buf, size, offset);
-		if (now <= 0)
+		if (now == 0) {
+			errno = ENOSPC;
+			return -1;
+		}
+		if (now < 0)
 			return now;
 		size -= now;
 		buf += now;
@@ -60,7 +64,11 @@ int write_full(int fd, const void *buf, size_t size)
 
 	while (size) {
 		now = write(fd, buf, size);
-		if (now <= 0)
+		if (now == 0) {
+			errno = ENOSPC;
+			return -1;
+		}
+		if (now < 0)
 			return now;
 		size -= now;
 		buf += now;
-- 
2.21.0


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Re: [PATCH 1/2] libfile: Simplify read_full()

[Sascha Hauer]

On Mon, May 27, 2019 at 10:58:52PM -0700, Andrey Smirnov wrote:
> We can figure out the amount of written data by substracting 'insize'
> from 'size' so there is no need to keep a separate counter for that.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---
>  lib/libfile.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)

Applied, thanks

Sascha


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