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From: Stefano Brivio <sbrivio@redhat.com>
To: passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>,
	Laurent Vivier <lvivier@redhat.com>
Subject: [PATCH v2] iov: Fix coding style of basic (non-IOV_TAIL) parts
Date: Mon,  8 Dec 2025 01:18:55 +0100	[thread overview]
Message-ID: <20251208001855.390887-1-sbrivio@redhat.com> (raw)

I happened to touch these functions for a change that turned out to be
unnecessary, but coding style and documentation could still benefit
from some rephrasing and fixes.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
v2: Make description of @offset consistent between iov_from_buf() and
    iov_to_buf()

 iov.c | 68 +++++++++++++++++++++++++----------------------------------
 1 file changed, 29 insertions(+), 39 deletions(-)

diff --git a/iov.c b/iov.c
index 8c74a59..ad726da 100644
--- a/iov.c
+++ b/iov.c
@@ -20,24 +20,21 @@
  * Contributions after 2012-01-13 are licensed under the terms of the
  * GNU GPL, version 2 or (at your option) any later version.
  */
+
 #include <sys/socket.h>
 
 #include "util.h"
 #include "iov.h"
 
-
 /**
- * iov_skip_bytes() - Skip leading bytes of an IO vector
- * @iov:	IO vector
+ * iov_skip_bytes() - Find index and offset in iovec array given byte offset
+ * @iov:	iovec array
  * @n:		Number of entries in @iov
- * @skip:	Number of leading bytes of @iov to skip
- * @offset:	Offset of first unskipped byte in its @iov entry
+ * @skip:	Byte offset: leading bytes of @iov to skip
+ * @offset:	Offset within matching @iov entry, set on return, can be NULL
  *
- * Return: index I of individual struct iovec which contains the byte at @skip
- *         bytes into the vector (as though all its buffers were contiguous).
- *         If @offset is non-NULL, update it to the offset of that byte within
- *         @iov[I] (guaranteed to be less than @iov[I].iov_len) If the whole
- *         vector has <= @skip bytes, return @n.
+ * Return: index of iovec array containing the @skip byte counted as if buffers
+ *	   were contiguous. If iovec has less than @skip bytes, return @n.
  */
 size_t iov_skip_bytes(const struct iovec *iov, size_t n,
 		      size_t skip, size_t *offset)
@@ -57,17 +54,14 @@ size_t iov_skip_bytes(const struct iovec *iov, size_t n,
 }
 
 /**
- * iov_from_buf() - Copy data from a buffer to an I/O vector (struct iovec)
- *                  efficiently.
- *
- * @iov:       Pointer to the array of struct iovec describing the
- *             scatter/gather I/O vector.
- * @iov_cnt:   Number of elements in the iov array.
- * @offset:    Byte offset in the iov array where copying should start.
- * @buf:       Pointer to the source buffer containing the data to copy.
- * @bytes:     Total number of bytes to copy from buf to iov.
+ * iov_from_buf() - Copy from flat buffer to iovec array
+ * @iov:	Destination iovec array
+ * @iov_cnt:	Number of elements in the iovec array
+ * @offset:	Destination offset in @iov counted as if buffers were contiguous
+ * @buf:	Source buffer
+ * @bytes:	Bytes to copy
  *
- * Return: the number of bytes successfully copied.
+ * Return: number of bytes copied
  */
 size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
 		    size_t offset, const void *buf, size_t bytes)
@@ -78,12 +72,12 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
 	if (__builtin_constant_p(bytes) && iov_cnt &&
 		offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
 		memcpy((char *)iov[0].iov_base + offset, buf, bytes);
+
 		return bytes;
 	}
 
 	i = iov_skip_bytes(iov, iov_cnt, offset, &offset);
 
-	/* copying data */
 	for (copied = 0; copied < bytes && i < iov_cnt; i++) {
 		size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
 
@@ -97,17 +91,14 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
 }
 
 /**
- * iov_to_buf() - Copy data from a scatter/gather I/O vector (struct iovec) to
- *		  a buffer efficiently.
- *
- * @iov:       Pointer to the array of struct iovec describing the scatter/gather
- *             I/O vector.
- * @iov_cnt:   Number of elements in the iov array.
- * @offset:    Offset within the first element of iov from where copying should start.
- * @buf:       Pointer to the destination buffer where data will be copied.
- * @bytes:     Total number of bytes to copy from iov to buf.
+ * iov_to_buf() - Copy from iovec to flat buffer
+ * @iov:	Source iovec array
+ * @iov_cnt:	Number of elements in iovec array
+ * @offset:	Source offset in @iov counted as if buffers were contiguous
+ * @buf:	Destination buffer
+ * @bytes:	Bytes to copy
  *
- * Return: the number of bytes successfully copied.
+ * Return: number of bytes copied
  */
 size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
 		  size_t offset, void *buf, size_t bytes)
@@ -118,15 +109,17 @@ size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
 	if (__builtin_constant_p(bytes) && iov_cnt &&
 		offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
 		memcpy(buf, (char *)iov[0].iov_base + offset, bytes);
+
 		return bytes;
 	}
 
 	i = iov_skip_bytes(iov, iov_cnt, offset, &offset);
 
-	/* copying data */
 	for (copied = 0; copied < bytes && i < iov_cnt; i++) {
 		size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
+
 		ASSERT(iov[i].iov_base);
+
 		memcpy((char *)buf + copied, (char *)iov[i].iov_base + offset,
 		       len);
 		copied += len;
@@ -137,14 +130,11 @@ size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
 }
 
 /**
- * iov_size() - Calculate the total size of a scatter/gather I/O vector
- *              (struct iovec).
+ * iov_size() - Calculate total data size of iovec
+ * @iov:	Source iovec array
+ * @iov_cnt:	Number of elements in iovec array
  *
- * @iov:       Pointer to the array of struct iovec describing the
- *             scatter/gather I/O vector.
- * @iov_cnt:   Number of elements in the iov array.
- *
- * Return: the total size in bytes.
+ * Return: total size in bytes
  */
 size_t iov_size(const struct iovec *iov, size_t iov_cnt)
 {
-- 
2.43.0


             reply	other threads:[~2025-12-08  0:18 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-08  0:18 Stefano Brivio [this message]
2025-12-08  2:17 ` David Gibson

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