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From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 06/19] devfs: Fix incorrect error check for cdev->ops->lseek()
Date: Mon, 28 Jan 2019 22:55:36 -0800	[thread overview]
Message-ID: <20190129065549.29161-7-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190129065549.29161-1-andrew.smirnov@gmail.com>

Cdev->ops->lseek() will either return a negative error code on failure
or requested position on success. In order to properly check for
errors we need to test if the return value is negative, not just that
it's not -1.

Returning ret - cdev->offset, doesn't appear to be correct either,
even if ret is -1, since on failure this will lead us to return (-1 -
cdev->offset). Simplify that part by just returning 'pos', which is
what we'd end up returning on success in original code as well.

Third, make sure to return -ENOSYS, when no .lseek() callback is
provided.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 fs/devfs.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/devfs.c b/fs/devfs.c
index 81ae2c25a..ae5e6475b 100644
--- a/fs/devfs.c
+++ b/fs/devfs.c
@@ -60,15 +60,19 @@ static int devfs_write(struct device_d *_dev, FILE *f, const void *buf, size_t s
 static loff_t devfs_lseek(struct device_d *_dev, FILE *f, loff_t pos)
 {
 	struct cdev *cdev = f->priv;
-	loff_t ret = -1;
+	loff_t ret;
 
-	if (cdev->ops->lseek)
+	if (cdev->ops->lseek) {
 		ret = cdev->ops->lseek(cdev, pos + cdev->offset);
+		if (ret < 0)
+			return ret;
+	} else {
+		return -ENOSYS;
+	}
 
-	if (ret != -1)
-		f->pos = pos;
+	f->pos = pos;
 
-	return ret - cdev->offset;
+	return pos;
 }
 
 static int devfs_erase(struct device_d *_dev, FILE *f, loff_t count, loff_t offset)
-- 
2.20.1


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  parent reply	other threads:[~2019-01-29  6:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29  6:55 [PATCH v2 00/19] 32-bit lseek and /dev/mem fixes/improvements Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 01/19] commands: Move mem_parse_options() to lib/misc.c Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 02/19] commands: Get rid of mem_rw_buf Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 03/19] commands: Move /dev/mem driver to drivers/misc Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 04/19] nvmem: Do not use DEVFS_IS_CHARACTER_DEV Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 05/19] common: firmware: Don't use FILE_SIZE_STREAM directly Andrey Smirnov
2019-01-29  6:55 ` Andrey Smirnov [this message]
2019-01-29  6:55 ` [PATCH v2 07/19] fs: Update FILE position in lseek() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 08/19] fs: Drop trivial .lseek() implementaitons in FS drivers Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 09/19] devfs: Drop dev_lseek_default() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 10/19] fs: devfs: Change .lseek callbacks to return 'int' Andrey Smirnov
2019-02-04 14:32   ` Sascha Hauer
2019-01-29  6:55 ` [PATCH v2 11/19] fs: Do not use IS_ERR_VALUE() to validate offset in lseek() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 12/19] fs: Simplify new position calculation " Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 13/19] fs: Share code between mem_write()/mem_read() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 14/19] fs: Avoid division in mem_copy() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 15/19] fs: Report actual data processed by mem_copy() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 16/19] fs: Introduce mem_read_nofail() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 17/19] commands: md: Do not use memmap() Andrey Smirnov
2019-02-04 13:57   ` Sascha Hauer
2019-02-04 19:35     ` Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory Andrey Smirnov
2019-01-29  8:48   ` Sascha Hauer
2019-01-29 20:40     ` Andrey Smirnov
2019-01-29 21:09       ` Sam Ravnborg
2019-01-31 10:54       ` Peter Mamonov
2019-01-31 12:50         ` Peter Mamonov
2019-02-01  7:47           ` Sascha Hauer
2019-02-01 10:25             ` Peter Mamonov
2019-02-02  1:07               ` Andrey Smirnov
2019-02-02  0:35             ` Andrey Smirnov
2019-02-04  7:40               ` Sascha Hauer
2019-01-31 20:17         ` Andrey Smirnov
2019-02-01 10:14           ` Peter Mamonov
2019-01-29  6:55 ` [PATCH v2 19/19] libfile: Fix incorrect lseek check in open_and_lseek() Andrey Smirnov

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