From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1aB5b3-0006zI-MR for user-mode-linux-devel@lists.sourceforge.net; Mon, 21 Dec 2015 18:54:13 +0000 Received: from ivanoab4.miniserver.com ([78.31.104.92]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:AES128-SHA:128) (Exim 4.76) id 1aB5b2-0006gY-CZ for user-mode-linux-devel@lists.sourceforge.net; Mon, 21 Dec 2015 18:54:13 +0000 From: Anton Ivanov Date: Mon, 21 Dec 2015 18:54:00 +0000 Message-Id: <1450724041-708451-1-git-send-email-aivanov@brocade.com> List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: [uml-devel] [PATCH 1/2] Update UBD to use pread/pwrite family of functions To: user-mode-linux-devel@lists.sourceforge.net Cc: richard@nod.at, Anton Ivanov This decreases the number of syscalls per read/write by half. Signed-off-by: Anton Ivanov --- arch/um/drivers/ubd_kern.c | 27 +++++---------------------- arch/um/include/shared/os.h | 2 ++ arch/um/os-Linux/file.c | 19 +++++++++++++++++++ 3 files changed, 26 insertions(+), 22 deletions(-) diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index e8ab93c..39ba207 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -535,11 +535,7 @@ static int read_cow_bitmap(int fd, void *buf, int offset, int len) { int err; - err = os_seek_file(fd, offset); - if (err < 0) - return err; - - err = os_read_file(fd, buf, len); + err = os_pread_file(fd, buf, len, offset); if (err < 0) return err; @@ -1377,14 +1373,8 @@ static int update_bitmap(struct io_thread_req *req) if(req->cow_offset == -1) return 0; - n = os_seek_file(req->fds[1], req->cow_offset); - if(n < 0){ - printk("do_io - bitmap lseek failed : err = %d\n", -n); - return 1; - } - - n = os_write_file(req->fds[1], &req->bitmap_words, - sizeof(req->bitmap_words)); + n = os_pwrite_file(req->fds[1], &req->bitmap_words, + sizeof(req->bitmap_words), req->cow_offset); if(n != sizeof(req->bitmap_words)){ printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, req->fds[1]); @@ -1399,7 +1389,6 @@ static void do_io(struct io_thread_req *req) char *buf; unsigned long len; int n, nsectors, start, end, bit; - int err; __u64 off; if (req->op == UBD_FLUSH) { @@ -1428,18 +1417,12 @@ static void do_io(struct io_thread_req *req) len = (end - start) * req->sectorsize; buf = &req->buffer[start * req->sectorsize]; - err = os_seek_file(req->fds[bit], off); - if(err < 0){ - printk("do_io - lseek failed : err = %d\n", -err); - req->error = 1; - return; - } if(req->op == UBD_READ){ n = 0; do { buf = &buf[n]; len -= n; - n = os_read_file(req->fds[bit], buf, len); + n = os_pread_file(req->fds[bit], buf, len, off); if (n < 0) { printk("do_io - read failed, err = %d " "fd = %d\n", -n, req->fds[bit]); @@ -1449,7 +1432,7 @@ static void do_io(struct io_thread_req *req) } while((n < len) && (n != 0)); if (n < len) memset(&buf[n], 0, len - n); } else { - n = os_write_file(req->fds[bit], buf, len); + n = os_pwrite_file(req->fds[bit], buf, len, off); if(n != len){ printk("do_io - write failed err = %d " "fd = %d\n", -n, req->fds[bit]); diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index 868e6c3..7a04ddd 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -146,6 +146,8 @@ extern int os_read_file(int fd, void *buf, int len); extern int os_write_file(int fd, const void *buf, int count); extern int os_sync_file(int fd); extern int os_file_size(const char *file, unsigned long long *size_out); +extern int os_pread_file(int fd, void *buf, int len, unsigned long long offset); +extern int os_pwrite_file(int fd, const void *buf, int count, unsigned long long offset); extern int os_file_modtime(const char *file, unsigned long *modtime); extern int os_pipe(int *fd, int stream, int close_on_exec); extern int os_set_fd_async(int fd); diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c index 26e0164..2db18cb 100644 --- a/arch/um/os-Linux/file.c +++ b/arch/um/os-Linux/file.c @@ -264,6 +264,15 @@ int os_read_file(int fd, void *buf, int len) return n; } +int os_pread_file(int fd, void *buf, int len, unsigned long long offset) +{ + int n = pread(fd, buf, len, offset); + + if (n < 0) + return -errno; + return n; +} + int os_write_file(int fd, const void *buf, int len) { int n = write(fd, (void *) buf, len); @@ -282,6 +291,16 @@ int os_sync_file(int fd) return n; } +int os_pwrite_file(int fd, const void *buf, int len, unsigned long long offset) +{ + int n = pwrite(fd, (void *) buf, len, offset); + + if (n < 0) + return -errno; + return n; +} + + int os_file_size(const char *file, unsigned long long *size_out) { struct uml_stat buf; -- 2.1.4 ------------------------------------------------------------------------------ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel