Am 29.04.2016 um 22:08 hat Eric Blake geschrieben:
> Sector-based blk_write() should die; switch to byte-based
> blk_pwrite() instead. Likewise for blk_read().
>
> Greatly simplifies the code, now that we let the block layer
> take care of alignment and read-modify-write on our behalf :)
>
> Signed-off-by: Eric Blake <ebl...@redhat.com>
> ---
> hw/sd/sd.c | 46 +++-------------------------------------------
> 1 file changed, 3 insertions(+), 43 deletions(-)
>
> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
> index b66e5d2..3c2f2f1 100644
> --- a/hw/sd/sd.c
> +++ b/hw/sd/sd.c
> @@ -1577,57 +1577,17 @@ send_response:
>
> static void sd_blk_read(SDState *sd, uint64_t addr, uint32_t len)
> {
> - uint64_t end = addr + len;
> -
> DPRINTF("sd_blk_read: addr = 0x%08llx, len = %d\n",
> (unsigned long long) addr, len);
> - if (!sd->blk || blk_read(sd->blk, addr >> 9, sd->buf, 1) < 0) {
> + if (!sd->blk || blk_pread(sd->blk, addr, sd->data, len) < 0) {
> fprintf(stderr, "sd_blk_read: read error on host side\n");
> - return;
> }
> -
> - if (end > (addr & ~511) + 512) {
> - memcpy(sd->data, sd->buf + (addr & 511), 512 - (addr & 511));
> -
> - if (blk_read(sd->blk, end >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_read: read error on host side\n");
> - return;
> - }
> - memcpy(sd->data + 512 - (addr & 511), sd->buf, end & 511);
> - } else
> - memcpy(sd->data, sd->buf + (addr & 511), len);
> }
We can remove sd->buf from SDState, it should be unused now.
I'm not sure why a temporary buffer was ever included in the VMState,
but I guess we can make it a VMSTATE_UNUSED_BUFFER().
> static void sd_blk_write(SDState *sd, uint64_t addr, uint32_t len)
> {
> - uint64_t end = addr + len;
> -
> - if ((addr & 511) || len < 512)
> - if (!sd->blk || blk_read(sd->blk, addr >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_write: read error on host side\n");
> - return;
> - }
> -
> - if (end > (addr & ~511) + 512) {
> - memcpy(sd->buf + (addr & 511), sd->data, 512 - (addr & 511));
> - if (blk_write(sd->blk, addr >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_write: write error on host side\n");
> - return;
> - }
> -
> - if (blk_read(sd->blk, end >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_write: read error on host side\n");
> - return;
> - }
> - memcpy(sd->buf, sd->data + 512 - (addr & 511), end & 511);
> - if (blk_write(sd->blk, end >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_write: write error on host side\n");
> - }
> - } else {
> - memcpy(sd->buf + (addr & 511), sd->data, len);
> - if (!sd->blk || blk_write(sd->blk, addr >> 9, sd->buf, 1) < 0) {
> - fprintf(stderr, "sd_blk_write: write error on host side\n");
> - }
> + if (!sd->blk || blk_pwrite(sd->blk, addr, sd->buf, len, 0) < 0) {
I said "should" instead of "is" above because this line is buggy.
sd->data should probably be used instead.
Kevin
