From: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx>
If the read or write buffer size associated with the command sent
through the mmc_blk_ioctl is zero, do not prepare data buffer.
This enables a ioctl(2) call to for instance send a MMC_SWITCH to set
a byte in the ext_csd.
Signed-off-by: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx>
Signed-off-by: Chris Ball <cjb@xxxxxxxxxx>
---
Upstream commit 4d6144de8ba263eb3691a737c547e5b2fdc45287.
Please apply to stable for 3.0, 3.1 and 3.2, I've tested that
it applies cleanly to each. Fixes a NULL dereference oops via
ioctl.
drivers/mmc/card/block.c | 82 +++++++++++++++++++++++++---------------------
1 files changed, 45 insertions(+), 37 deletions(-)
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 12096cc..4d29b30 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -336,6 +336,9 @@ static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user(
goto idata_err;
}
+ if (!idata->buf_bytes)
+ return idata;
+
idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
if (!idata->buf) {
err = -ENOMEM;
@@ -382,25 +385,6 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
if (IS_ERR(idata))
return PTR_ERR(idata);
- cmd.opcode = idata->ic.opcode;
- cmd.arg = idata->ic.arg;
- cmd.flags = idata->ic.flags;
-
- data.sg = &sg;
- data.sg_len = 1;
- data.blksz = idata->ic.blksz;
- data.blocks = idata->ic.blocks;
-
- sg_init_one(data.sg, idata->buf, idata->buf_bytes);
-
- if (idata->ic.write_flag)
- data.flags = MMC_DATA_WRITE;
- else
- data.flags = MMC_DATA_READ;
-
- mrq.cmd = &cmd;
- mrq.data = &data;
-
md = mmc_blk_get(bdev->bd_disk);
if (!md) {
err = -EINVAL;
@@ -413,6 +397,48 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
goto cmd_done;
}
+ cmd.opcode = idata->ic.opcode;
+ cmd.arg = idata->ic.arg;
+ cmd.flags = idata->ic.flags;
+
+ if (idata->buf_bytes) {
+ data.sg = &sg;
+ data.sg_len = 1;
+ data.blksz = idata->ic.blksz;
+ data.blocks = idata->ic.blocks;
+
+ sg_init_one(data.sg, idata->buf, idata->buf_bytes);
+
+ if (idata->ic.write_flag)
+ data.flags = MMC_DATA_WRITE;
+ else
+ data.flags = MMC_DATA_READ;
+
+ /* data.flags must already be set before doing this. */
+ mmc_set_data_timeout(&data, card);
+
+ /* Allow overriding the timeout_ns for empirical tuning. */
+ if (idata->ic.data_timeout_ns)
+ data.timeout_ns = idata->ic.data_timeout_ns;
+
+ if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
+ /*
+ * Pretend this is a data transfer and rely on the
+ * host driver to compute timeout. When all host
+ * drivers support cmd.cmd_timeout for R1B, this
+ * can be changed to:
+ *
+ * mrq.data = NULL;
+ * cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
+ */
+ data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
+ }
+
+ mrq.data = &data;
+ }
+
+ mrq.cmd = &cmd;
+
mmc_claim_host(card->host);
if (idata->ic.is_acmd) {
@@ -421,24 +447,6 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
goto cmd_rel_host;
}
- /* data.flags must already be set before doing this. */
- mmc_set_data_timeout(&data, card);
- /* Allow overriding the timeout_ns for empirical tuning. */
- if (idata->ic.data_timeout_ns)
- data.timeout_ns = idata->ic.data_timeout_ns;
-
- if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
- /*
- * Pretend this is a data transfer and rely on the host driver
- * to compute timeout. When all host drivers support
- * cmd.cmd_timeout for R1B, this can be changed to:
- *
- * mrq.data = NULL;
- * cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
- */
- data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
- }
-
mmc_wait_for_req(card->host, &mrq);
if (cmd.error) {
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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