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[79.55.110.244]) by smtp.gmail.com with ESMTPSA id h20-20020a05600c351400b003b4935f04a4sm7222121wmq.5.2022.11.25.07.38.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Nov 2022 07:38:31 -0800 (PST) From: "Fabio M. De Francesco" To: netdev@vger.kernel.org, Anirudh Venkataramanan Cc: Ira Weiny , Anirudh Venkataramanan Subject: Re: [PATCH v2 net-next 3/6] cassini: Use page_address() instead of kmap_atomic() Date: Fri, 25 Nov 2022 16:38:30 +0100 Message-ID: <3389596.QJadu78ljV@suse> In-Reply-To: <20221123205219.31748-4-anirudh.venkataramanan@intel.com> References: <20221123205219.31748-1-anirudh.venkataramanan@intel.com> <20221123205219.31748-4-anirudh.venkataramanan@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On mercoled=EC 23 novembre 2022 21:52:16 CET Anirudh Venkataramanan wrote: > Pages for Rx buffers are allocated in cas_page_alloc() using either > GFP_ATOMIC or GFP_KERNEL. Memory allocated with GFP_KERNEL/GFP_ATOMIC can= 't > come from highmem and so there's no need to kmap() them. Just use > page_address() instead. This makes the variable 'addr' unnecessary, so > remove it too. >=20 > Note that kmap_atomic() disables preemption and page-fault processing, > but page_address() doesn't. When removing uses of kmap_atomic(), one has = to > check if the code being executed between the map/unmap implicitly depends > on page-faults and/or preemption being disabled. If yes, then code to > disable page-faults and/or preemption should also be added for functional > correctness. That however doesn't appear to be the case here, so just > page_address() is used. >=20 > I don't have hardware, so this change has only been compile tested. >=20 > Cc: Ira Weiny > Cc: Fabio M. De Francesco > Signed-off-by: Anirudh Venkataramanan > --- > v1 -> v2: Update commit message > --- > drivers/net/ethernet/sun/cassini.c | 34 ++++++++++-------------------- > 1 file changed, 11 insertions(+), 23 deletions(-) Reviewed-by: Fabio M. De Francesco Thanks, =46abio > diff --git a/drivers/net/ethernet/sun/cassini.c > b/drivers/net/ethernet/sun/cassini.c index 0aca193..2f66cfc 100644 > --- a/drivers/net/ethernet/sun/cassini.c > +++ b/drivers/net/ethernet/sun/cassini.c > @@ -1915,7 +1915,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct > cas_rx_comp *rxc, int off, swivel =3D RX_SWIVEL_OFF_VAL; > struct cas_page *page; > struct sk_buff *skb; > - void *addr, *crcaddr; > + void *crcaddr; > __sum16 csum; > char *p; >=20 > @@ -1936,7 +1936,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct > cas_rx_comp *rxc, skb_reserve(skb, swivel); >=20 > p =3D skb->data; > - addr =3D crcaddr =3D NULL; > + crcaddr =3D NULL; > if (hlen) { /* always copy header pages */ > i =3D CAS_VAL(RX_COMP2_HDR_INDEX, words[1]); > page =3D cp->rx_pages[CAS_VAL(RX_INDEX_RING, i)] [CAS_VAL(RX_INDEX_NUM, i)]; > @@ -1948,12 +1948,10 @@ static int cas_rx_process_pkt(struct cas *cp, str= uct > cas_rx_comp *rxc, i +=3D cp->crc_size; > dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr +=20 off, > i, DMA_FROM_DEVICE); > - addr =3D cas_page_map(page->buffer); > - memcpy(p, addr + off, i); > + memcpy(p, page_address(page->buffer) + off, i); > dma_sync_single_for_device(&cp->pdev->dev, > page->dma_addr + off, i, > DMA_FROM_DEVICE); > - cas_page_unmap(addr); > RX_USED_ADD(page, 0x100); > p +=3D hlen; > swivel =3D 0; > @@ -1984,12 +1982,11 @@ static int cas_rx_process_pkt(struct cas *cp, str= uct > cas_rx_comp *rxc, /* make sure we always copy a header */ > swivel =3D 0; > if (p =3D=3D (char *) skb->data) { /* not split */ > - addr =3D cas_page_map(page->buffer); > - memcpy(p, addr + off, RX_COPY_MIN); > + memcpy(p, page_address(page->buffer) + off, > + RX_COPY_MIN); > dma_sync_single_for_device(&cp->pdev->dev, > page->dma_addr=20 + off, i, > =20 DMA_FROM_DEVICE); > - cas_page_unmap(addr); > off +=3D RX_COPY_MIN; > swivel =3D RX_COPY_MIN; > RX_USED_ADD(page, cp->mtu_stride); > @@ -2036,10 +2033,8 @@ static int cas_rx_process_pkt(struct cas *cp, stru= ct > cas_rx_comp *rxc, RX_USED_ADD(page, hlen + cp->crc_size); > } >=20 > - if (cp->crc_size) { > - addr =3D cas_page_map(page->buffer); > - crcaddr =3D addr + off + hlen; > - } > + if (cp->crc_size) > + crcaddr =3D page_address(page->buffer) + off +=20 hlen; >=20 > } else { > /* copying packet */ > @@ -2061,12 +2056,10 @@ static int cas_rx_process_pkt(struct cas *cp, str= uct > cas_rx_comp *rxc, i +=3D cp->crc_size; > dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr +=20 off, > i, DMA_FROM_DEVICE); > - addr =3D cas_page_map(page->buffer); > - memcpy(p, addr + off, i); > + memcpy(p, page_address(page->buffer) + off, i); > dma_sync_single_for_device(&cp->pdev->dev, > page->dma_addr + off, i, > DMA_FROM_DEVICE); > - cas_page_unmap(addr); > if (p =3D=3D (char *) skb->data) /* not split */ > RX_USED_ADD(page, cp->mtu_stride); > else > @@ -2081,20 +2074,17 @@ static int cas_rx_process_pkt(struct cas *cp, str= uct > cas_rx_comp *rxc, page->dma_addr, > dlen + cp- >crc_size, > DMA_FROM_DEVICE); > - addr =3D cas_page_map(page->buffer); > - memcpy(p, addr, dlen + cp->crc_size); > + memcpy(p, page_address(page->buffer), dlen + cp- >crc_size); > dma_sync_single_for_device(&cp->pdev->dev, > page->dma_addr, > dlen + cp- >crc_size, > =20 DMA_FROM_DEVICE); > - cas_page_unmap(addr); > RX_USED_ADD(page, dlen + cp->crc_size); > } > end_copy_pkt: > - if (cp->crc_size) { > - addr =3D NULL; > + if (cp->crc_size) > crcaddr =3D skb->data + alloclen; > - } > + > skb_put(skb, alloclen); > } >=20 > @@ -2103,8 +2093,6 @@ static int cas_rx_process_pkt(struct cas *cp, struct > cas_rx_comp *rxc, /* checksum includes FCS. strip it out. */ > csum =3D csum_fold(csum_partial(crcaddr, cp->crc_size, > csum_unfold(csum))); > - if (addr) > - cas_page_unmap(addr); > } > skb->protocol =3D eth_type_trans(skb, cp->dev); > if (skb->protocol =3D=3D htons(ETH_P_IP)) { > -- > 2.37.2