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mmc: core: check for zero length ioctl data
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@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
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@ -266,6 +266,9 @@ static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user(
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goto idata_err;
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}
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if (!idata->buf_bytes)
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return idata;
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idata->buf = kzalloc(idata->buf_bytes, GFP_KERNEL);
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if (!idata->buf) {
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err = -ENOMEM;
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@ -312,25 +315,6 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
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if (IS_ERR(idata))
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return PTR_ERR(idata);
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cmd.opcode = idata->ic.opcode;
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cmd.arg = idata->ic.arg;
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cmd.flags = idata->ic.flags;
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data.sg = &sg;
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data.sg_len = 1;
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data.blksz = idata->ic.blksz;
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data.blocks = idata->ic.blocks;
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sg_init_one(data.sg, idata->buf, idata->buf_bytes);
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if (idata->ic.write_flag)
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data.flags = MMC_DATA_WRITE;
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else
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data.flags = MMC_DATA_READ;
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mrq.cmd = &cmd;
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mrq.data = &data;
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md = mmc_blk_get(bdev->bd_disk);
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if (!md) {
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err = -EINVAL;
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@ -343,6 +327,48 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
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goto cmd_done;
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}
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cmd.opcode = idata->ic.opcode;
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cmd.arg = idata->ic.arg;
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cmd.flags = idata->ic.flags;
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if (idata->buf_bytes) {
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data.sg = &sg;
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data.sg_len = 1;
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data.blksz = idata->ic.blksz;
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data.blocks = idata->ic.blocks;
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sg_init_one(data.sg, idata->buf, idata->buf_bytes);
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if (idata->ic.write_flag)
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data.flags = MMC_DATA_WRITE;
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else
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data.flags = MMC_DATA_READ;
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/* data.flags must already be set before doing this. */
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mmc_set_data_timeout(&data, card);
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/* Allow overriding the timeout_ns for empirical tuning. */
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if (idata->ic.data_timeout_ns)
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data.timeout_ns = idata->ic.data_timeout_ns;
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if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
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/*
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* Pretend this is a data transfer and rely on the
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* host driver to compute timeout. When all host
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* drivers support cmd.cmd_timeout for R1B, this
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* can be changed to:
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*
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* mrq.data = NULL;
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* cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
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*/
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data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
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}
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mrq.data = &data;
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}
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mrq.cmd = &cmd;
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mmc_claim_host(card->host);
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if (idata->ic.is_acmd) {
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@ -351,24 +377,6 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
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goto cmd_rel_host;
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}
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/* data.flags must already be set before doing this. */
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mmc_set_data_timeout(&data, card);
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/* Allow overriding the timeout_ns for empirical tuning. */
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if (idata->ic.data_timeout_ns)
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data.timeout_ns = idata->ic.data_timeout_ns;
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if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
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/*
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* Pretend this is a data transfer and rely on the host driver
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* to compute timeout. When all host drivers support
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* cmd.cmd_timeout for R1B, this can be changed to:
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*
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* mrq.data = NULL;
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* cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
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*/
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data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
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}
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mmc_wait_for_req(card->host, &mrq);
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if (cmd.error) {
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