* Linus Torvalds [Fri, 02 Jan 2009 08:42:04 -0800]:
> Yes, this one is a real patience diff change, but it's also the same one
> that I've seen in the google fanboi findings. What google did _not_ show
> was any real-life examples, or anybody doing any critical analysis.
This comes a bit late and maybe it's redundant, but somebody just sent
to a Debian mailing list a patch that was hard to read, and patience
improved it. (I realize it's quite similar in spirit to the "toy
patience example" that google returns, but this at list is a *real*
example where patience helped me read a patch.)
I'm also attaching bzr diff output, because it's still more readable
IMHO. (I realize that's independent of patience, as you explained, but
I'm making a point that it'd be nice to have this addressed by somebody
knowledgeable.)
Thanks,
--
Adeodato Simó dato at net.com.org.es
Debian Developer adeodato at debian.org
- Are you sure we're good?
- Always.
-- Rory and Lorelai
diff --git util_sock.c util_sock.c
index e20768e..f7b9145 100644
--- util_sock.c
+++ util_sock.c
@@ -1037,40 +1037,109 @@ NTSTATUS read_data(int fd, char *buffer, size_t N)
}
/****************************************************************************
- Write data to a fd.
+ Write all data from an iov array
****************************************************************************/
-ssize_t write_data(int fd, const char *buffer, size_t N)
+ssize_t write_data_iov(int fd, const struct iovec *orig_iov, int iovcnt)
{
- size_t total=0;
- ssize_t ret;
- char addr[INET6_ADDRSTRLEN];
+ int i;
+ size_t to_send;
+ ssize_t thistime;
+ size_t sent;
+ struct iovec *iov_copy, *iov;
- while (total < N) {
- ret = sys_write(fd,buffer + total,N - total);
+ to_send = 0;
+ for (i=0; i<iovcnt; i++) {
+ to_send += orig_iov[i].iov_len;
+ }
- if (ret == -1) {
- if (fd == get_client_fd()) {
- /* Try and give an error message saying
- * what client failed. */
- DEBUG(0,("write_data: write failure in "
- "writing to client %s. Error %s\n",
- get_peer_addr(fd,addr,sizeof(addr)),
- strerror(errno) ));
- } else {
- DEBUG(0,("write_data: write failure. "
- "Error = %s\n", strerror(errno) ));
+ thistime = sys_writev(fd, orig_iov, iovcnt);
+ if ((thistime <= 0) || (thistime == to_send)) {
+ return thistime;
+ }
+ sent = thistime;
+
+ /*
+ * We could not send everything in one call. Make a copy of iov that
+ * we can mess with. We keep a copy of the array start in iov_copy for
+ * the TALLOC_FREE, because we're going to modify iov later on,
+ * discarding elements.
+ */
+
+ iov_copy = (struct iovec *)TALLOC_MEMDUP(
+ talloc_tos(), orig_iov, sizeof(struct iovec) * iovcnt);
+
+ if (iov_copy == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ iov = iov_copy;
+
+ while (sent < to_send) {
+ /*
+ * We have to discard "thistime" bytes from the beginning
+ * iov array, "thistime" contains the number of bytes sent
+ * via writev last.
+ */
+ while (thistime > 0) {
+ if (thistime < iov[0].iov_len) {
+ char *new_base =
+ (char *)iov[0].iov_base + thistime;
+ iov[0].iov_base = new_base;
+ iov[0].iov_len -= thistime;
+ break;
}
- return -1;
+ thistime -= iov[0].iov_len;
+ iov += 1;
+ iovcnt -= 1;
}
- if (ret == 0) {
- return total;
+ thistime = sys_writev(fd, iov, iovcnt);
+ if (thistime <= 0) {
+ break;
}
+ sent += thistime;
+ }
+
+ TALLOC_FREE(iov_copy);
+ return sent;
+}
+
+/****************************************************************************
+ Write data to a fd.
+****************************************************************************/
+
+/****************************************************************************
+ Write data to a fd.
+****************************************************************************/
+
+ssize_t write_data(int fd, const char *buffer, size_t N)
+{
+ ssize_t ret;
+ struct iovec iov;
+
+ iov.iov_base = CONST_DISCARD(char *, buffer);
+ iov.iov_len = N;
+
+ ret = write_data_iov(fd, &iov, 1);
+ if (ret >= 0) {
+ return ret;
+ }
- total += ret;
+ if (fd == get_client_fd()) {
+ char addr[INET6_ADDRSTRLEN];
+ /*
+ * Try and give an error message saying what client failed.
+ */
+ DEBUG(0, ("write_data: write failure in writing to client %s. "
+ "Error %s\n", get_peer_addr(fd,addr,sizeof(addr)),
+ strerror(errno)));
+ } else {
+ DEBUG(0,("write_data: write failure. Error = %s\n",
+ strerror(errno) ));
}
- return (ssize_t)total;
+
+ return -1;
}
/****************************************************************************
diff --git util_sock.c util_sock.c
index e20768e..f7b9145 100644
--- util_sock.c
+++ util_sock.c
@@ -1037,40 +1037,109 @@ NTSTATUS read_data(int fd, char *buffer, size_t N)
}
/****************************************************************************
+ Write all data from an iov array
+****************************************************************************/
+
+ssize_t write_data_iov(int fd, const struct iovec *orig_iov, int iovcnt)
+{
+ int i;
+ size_t to_send;
+ ssize_t thistime;
+ size_t sent;
+ struct iovec *iov_copy, *iov;
+
+ to_send = 0;
+ for (i=0; i<iovcnt; i++) {
+ to_send += orig_iov[i].iov_len;
+ }
+
+ thistime = sys_writev(fd, orig_iov, iovcnt);
+ if ((thistime <= 0) || (thistime == to_send)) {
+ return thistime;
+ }
+ sent = thistime;
+
+ /*
+ * We could not send everything in one call. Make a copy of iov that
+ * we can mess with. We keep a copy of the array start in iov_copy for
+ * the TALLOC_FREE, because we're going to modify iov later on,
+ * discarding elements.
+ */
+
+ iov_copy = (struct iovec *)TALLOC_MEMDUP(
+ talloc_tos(), orig_iov, sizeof(struct iovec) * iovcnt);
+
+ if (iov_copy == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ iov = iov_copy;
+
+ while (sent < to_send) {
+ /*
+ * We have to discard "thistime" bytes from the beginning
+ * iov array, "thistime" contains the number of bytes sent
+ * via writev last.
+ */
+ while (thistime > 0) {
+ if (thistime < iov[0].iov_len) {
+ char *new_base =
+ (char *)iov[0].iov_base + thistime;
+ iov[0].iov_base = new_base;
+ iov[0].iov_len -= thistime;
+ break;
+ }
+ thistime -= iov[0].iov_len;
+ iov += 1;
+ iovcnt -= 1;
+ }
+
+ thistime = sys_writev(fd, iov, iovcnt);
+ if (thistime <= 0) {
+ break;
+ }
+ sent += thistime;
+ }
+
+ TALLOC_FREE(iov_copy);
+ return sent;
+}
+
+/****************************************************************************
+ Write data to a fd.
+****************************************************************************/
+
+/****************************************************************************
Write data to a fd.
****************************************************************************/
ssize_t write_data(int fd, const char *buffer, size_t N)
{
- size_t total=0;
ssize_t ret;
- char addr[INET6_ADDRSTRLEN];
+ struct iovec iov;
- while (total < N) {
- ret = sys_write(fd,buffer + total,N - total);
+ iov.iov_base = CONST_DISCARD(char *, buffer);
+ iov.iov_len = N;
- if (ret == -1) {
- if (fd == get_client_fd()) {
- /* Try and give an error message saying
- * what client failed. */
- DEBUG(0,("write_data: write failure in "
- "writing to client %s. Error %s\n",
- get_peer_addr(fd,addr,sizeof(addr)),
- strerror(errno) ));
- } else {
- DEBUG(0,("write_data: write failure. "
- "Error = %s\n", strerror(errno) ));
- }
- return -1;
- }
-
- if (ret == 0) {
- return total;
- }
+ ret = write_data_iov(fd, &iov, 1);
+ if (ret >= 0) {
+ return ret;
+ }
- total += ret;
+ if (fd == get_client_fd()) {
+ char addr[INET6_ADDRSTRLEN];
+ /*
+ * Try and give an error message saying what client failed.
+ */
+ DEBUG(0, ("write_data: write failure in writing to client %s. "
+ "Error %s\n", get_peer_addr(fd,addr,sizeof(addr)),
+ strerror(errno)));
+ } else {
+ DEBUG(0,("write_data: write failure. Error = %s\n",
+ strerror(errno) ));
}
- return (ssize_t)total;
+
+ return -1;
}
/****************************************************************************
--- util_sock.c
+++ util_sock.c
@@ -1037,40 +1037,109 @@
}
/****************************************************************************
+ Write all data from an iov array
+****************************************************************************/
+
+ssize_t write_data_iov(int fd, const struct iovec *orig_iov, int iovcnt)
+{
+ int i;
+ size_t to_send;
+ ssize_t thistime;
+ size_t sent;
+ struct iovec *iov_copy, *iov;
+
+ to_send = 0;
+ for (i=0; i<iovcnt; i++) {
+ to_send += orig_iov[i].iov_len;
+ }
+
+ thistime = sys_writev(fd, orig_iov, iovcnt);
+ if ((thistime <= 0) || (thistime == to_send)) {
+ return thistime;
+ }
+ sent = thistime;
+
+ /*
+ * We could not send everything in one call. Make a copy of iov that
+ * we can mess with. We keep a copy of the array start in iov_copy for
+ * the TALLOC_FREE, because we're going to modify iov later on,
+ * discarding elements.
+ */
+
+ iov_copy = (struct iovec *)TALLOC_MEMDUP(
+ talloc_tos(), orig_iov, sizeof(struct iovec) * iovcnt);
+
+ if (iov_copy == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ iov = iov_copy;
+
+ while (sent < to_send) {
+ /*
+ * We have to discard "thistime" bytes from the beginning
+ * iov array, "thistime" contains the number of bytes sent
+ * via writev last.
+ */
+ while (thistime > 0) {
+ if (thistime < iov[0].iov_len) {
+ char *new_base =
+ (char *)iov[0].iov_base + thistime;
+ iov[0].iov_base = new_base;
+ iov[0].iov_len -= thistime;
+ break;
+ }
+ thistime -= iov[0].iov_len;
+ iov += 1;
+ iovcnt -= 1;
+ }
+
+ thistime = sys_writev(fd, iov, iovcnt);
+ if (thistime <= 0) {
+ break;
+ }
+ sent += thistime;
+ }
+
+ TALLOC_FREE(iov_copy);
+ return sent;
+}
+
+/****************************************************************************
+ Write data to a fd.
+****************************************************************************/
+
+/****************************************************************************
Write data to a fd.
****************************************************************************/
ssize_t write_data(int fd, const char *buffer, size_t N)
{
- size_t total=0;
ssize_t ret;
- char addr[INET6_ADDRSTRLEN];
-
- while (total < N) {
- ret = sys_write(fd,buffer + total,N - total);
-
- if (ret == -1) {
- if (fd == get_client_fd()) {
- /* Try and give an error message saying
- * what client failed. */
- DEBUG(0,("write_data: write failure in "
- "writing to client %s. Error %s\n",
- get_peer_addr(fd,addr,sizeof(addr)),
- strerror(errno) ));
- } else {
- DEBUG(0,("write_data: write failure. "
- "Error = %s\n", strerror(errno) ));
- }
- return -1;
- }
-
- if (ret == 0) {
- return total;
- }
-
- total += ret;
- }
- return (ssize_t)total;
+ struct iovec iov;
+
+ iov.iov_base = CONST_DISCARD(char *, buffer);
+ iov.iov_len = N;
+
+ ret = write_data_iov(fd, &iov, 1);
+ if (ret >= 0) {
+ return ret;
+ }
+
+ if (fd == get_client_fd()) {
+ char addr[INET6_ADDRSTRLEN];
+ /*
+ * Try and give an error message saying what client failed.
+ */
+ DEBUG(0, ("write_data: write failure in writing to client %s. "
+ "Error %s\n", get_peer_addr(fd,addr,sizeof(addr)),
+ strerror(errno)));
+ } else {
+ DEBUG(0,("write_data: write failure. Error = %s\n",
+ strerror(errno) ));
+ }
+
+ return -1;
}
/****************************************************************************
