sfc: simplify DMA mask setting

Christoph says[1] that dma_set_mask_and_coherent() is smart enough to
 truncate the mask itself if it's too long.  So we can get rid of our
 "lop off one bit and retry" loop in efx_init_io().

[1]: https://www.spinics.net/lists/netdev/msg677266.html

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Edward Cree 2020-09-07 17:15:48 +01:00 committed by Jakub Kicinski
parent 60bd2a2d1f
commit 08bdbcae29
1 changed files with 1 additions and 11 deletions

View File

@ -1086,17 +1086,7 @@ int efx_init_io(struct efx_nic *efx, int bar, dma_addr_t dma_mask,
pci_set_master(pci_dev);
/* Set the PCI DMA mask. Try all possibilities from our
* genuine mask down to 32 bits, because some architectures
* (e.g. x86_64 with iommu_sac_force set) will allow 40 bit
* masks event though they reject 46 bit masks.
*/
while (dma_mask > 0x7fffffffUL) {
rc = dma_set_mask_and_coherent(&pci_dev->dev, dma_mask);
if (rc == 0)
break;
dma_mask >>= 1;
}
rc = dma_set_mask_and_coherent(&pci_dev->dev, dma_mask);
if (rc) {
netif_err(efx, probe, efx->net_dev,
"could not find a suitable DMA mask\n");