On Thu, Jun 29, 2017 at 04:02:11PM +0000, Chris Brandt wrote: > Personally, I think a buffer of raw data should be a 'u8 *', not a > 'unsigned short *'. That works, or you could make it a void pointer. (void *)foo + x and (u8 *)foo + x are equivalent in kernel code. > And, the parameter name "count" should really be something like "size" > or "length" (but that is still confusing because the passed array 'buf' > was designated as an array of "unsigned short *", so what would 'size' > really mean??) > > Anyway, that is the API that's in place today, so that's what I needed > to work with. You can change it. This is the kernel so you can change anything if it makes sense. > > > > > > 417 else > > 418 sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, > > (u32 *)buf, > > 419 count >> 2); > > 420 > > 421 /* if count was multiple of 4 */ > > 422 if (!(count & 0x3)) > > 423 return; > > 424 > > 425 buf8 = (u8 *)(buf + (count >> 2)); > > > > > > And this looks like the bug... buf is a u16 pointer but we're adding > > "count / sizeof(u32)" when we should be adding "count / (sizeof(*buf))". > > I agree this math does not work out to what I wanted because of the > differences in data types. > > Since I simply wanted to get a pointer to where I left off in the > buffer, maybe the most clear thing to do is just cast buf and do simple math: > > buf8 = (u8 *)buf + (count & ~3); > > > Do you agree? Sure. Unless you want to round up? regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
