Hi Dan,
On Wed, 6 Nov 2013, Dan Carpenter wrote:
> Hello Guennadi Liakhovetski,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 699834045f1e: "mmc: sh_mmcif: remove now superfluous
> sh_mmcif_host::data member" from Dec 26, 2011, leads to the following
> Smatch complaint:
>
> drivers/mmc/host/sh_mmcif.c:822 sh_mmcif_set_cmd()
> error: we previously assumed 'data' could be null (see line 787)
>
> drivers/mmc/host/sh_mmcif.c
> 786 /* WDAT / DATW */
> 787 if (data) {
> ^^^^
> Check.
>
> 788 tmp |= CMD_SET_WDAT;
> 789 switch (host->bus_width) {
> 790 case MMC_BUS_WIDTH_1:
> 791 tmp |= CMD_SET_DATW_1;
> 792 break;
> 793 case MMC_BUS_WIDTH_4:
> 794 tmp |= CMD_SET_DATW_4;
> 795 break;
> 796 case MMC_BUS_WIDTH_8:
> 797 tmp |= CMD_SET_DATW_8;
> 798 break;
> 799 default:
> 800 dev_err(&host->pd->dev, "Unsupported
> bus width.\n");
> 801 break;
> 802 }
> 803 switch (host->timing) {
> 804 case MMC_TIMING_UHS_DDR50:
> 805 /*
> 806 * MMC core will only set this timing,
> if the host
> 807 * advertises the MMC_CAP_UHS_DDR50
> capability. MMCIF
> 808 * implementations with this
> capability, e.g. sh73a0,
> 809 * will have to set it in their
> platform data.
> 810 */
> 811 tmp |= CMD_SET_DARS;
> 812 break;
> 813 }
> 814 }
> 815 /* DWEN */
> 816 if (opc == MMC_WRITE_BLOCK || opc ==
> MMC_WRITE_MULTIPLE_BLOCK)
> 817 tmp |= CMD_SET_DWEN;
> 818 /* CMLTE/CMD12EN */
> 819 if (opc == MMC_READ_MULTIPLE_BLOCK || opc ==
> MMC_WRITE_MULTIPLE_BLOCK) {
> 820 tmp |= CMD_SET_CMLTE | CMD_SET_CMD12EN;
> 821 sh_mmcif_bitset(host, MMCIF_CE_BLOCK_SET,
> 822 data->blocks << 16);
> ^^^^^^^^^^^^
> Dereference.
>
> We used to assume that host->data might be NULL but that mrq->data was
> a valid pointer. But now they are unified into one pointer.
Yes, formally this isn't correct, but in practice this is valid, because
for those two opcodes, handled in this "if" data cannot be NULL.
Thanks
Guennadi
>
> 823 }
> 824 /* RIDXC[1:0] check bits */
>
> regards,
> dan carpenter
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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