linux-kernel - [PATCH] Staging: zram: initialize device on first read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Thu, 17 Feb 2011 17:11:49 +0100
From:	Jerome Marchand <jmarchan@...hat.com>
To:	Nitin Gupta <ngupta@...are.org>
CC:	Greg Kroah-Hartman <gregkh@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH] Staging: zram: initialize device on first read


Currently the device is initialized when first write is done to the
device. Any read attempt before the first write would fail, including
"hidden" read the user may not know about (as for example if he tries
to write a partial block).

This patch initializes the device on first request, whether read or
write.

Signed-off-by: Jerome Marchand <jmarchan@...hat.com>
---
 zram_drv.c |   19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 5fdf9d2..aab4ec4 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -211,11 +211,6 @@ static void zram_read(struct zram *zram, struct bio *bio)
 	u32 index;
 	struct bio_vec *bvec;
 
-	if (unlikely(!zram->init_done)) {
-		bio_endio(bio, -ENXIO);
-		return;
-	}
-
 	zram_stat64_inc(zram, &zram->stats.num_reads);
 	index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
 
@@ -286,20 +281,15 @@ out:
 
 static void zram_write(struct zram *zram, struct bio *bio)
 {
-	int i, ret;
+	int i;
 	u32 index;
 	struct bio_vec *bvec;
 
-	if (unlikely(!zram->init_done)) {
-		ret = zram_init_device(zram);
-		if (ret)
-			goto out;
-	}
-
 	zram_stat64_inc(zram, &zram->stats.num_writes);
 	index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
 
 	bio_for_each_segment(bvec, bio, i) {
+		int ret;
 		u32 offset;
 		size_t clen;
 		struct zobj_header *zheader;
@@ -445,6 +435,11 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio)
 		return 0;
 	}
 
+	if (unlikely(!zram->init_done) && zram_init_device(zram)) {
+		bio_io_error(bio);
+		return 0;
+	}
+
 	switch (bio_data_dir(bio)) {
 	case READ:
 		zram_read(zram, bio);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/