From 133bc542db36e304f44fb520db9a3b8358b987f5 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Wed, 15 Dec 2021 15:43:04 -0600 Subject: [PATCH 1/2] MAINTAINERS: Add Logan Gunthorpe as P2PDMA maintainer Add a P2PDMA entry to make sure Logan is aware of changes to that area. Signed-off-by: Bjorn Helgaas Acked-by: Logan Gunthorpe --- MAINTAINERS | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 7a2345ce8521..ea59e32e1e81 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14717,6 +14717,19 @@ L: linux-pci@vger.kernel.org S: Supported F: Documentation/PCI/pci-error-recovery.rst +PCI PEER-TO-PEER DMA (P2PDMA) +M: Bjorn Helgaas +M: Logan Gunthorpe +L: linux-pci@vger.kernel.org +S: Supported +Q: https://patchwork.kernel.org/project/linux-pci/list/ +B: https://bugzilla.kernel.org +C: irc://irc.oftc.net/linux-pci +T: git git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git +F: Documentation/driver-api/pci/p2pdma.rst +F: drivers/pci/p2pdma.c +F: include/linux/pci-p2pdma.h + PCI MSI DRIVER FOR ALTERA MSI IP M: Joyce Ooi L: linux-pci@vger.kernel.org From 69f457b18fa2b9a793ce61e8d1cf295983aca3a9 Mon Sep 17 00:00:00 2001 From: Christophe JAILLET Date: Wed, 3 Nov 2021 22:16:53 +0100 Subject: [PATCH 2/2] PCI/P2PDMA: Use percpu_ref_tryget_live_rcu() inside RCU critical section MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since pci_alloc_p2pmem() has already called rcu_read_lock(), we're in an RCU read-side critical section and don't need to take the lock again. Use percpu_ref_tryget_live_rcu() instead of percpu_ref_tryget_live() to save a few cycles. [bhelgaas: commit log] Link: https://lore.kernel.org/r/ab80164f4d5b32f9e6240aa4863c3a147ff9c89f.1635974126.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET Signed-off-by: Bjorn Helgaas Reviewed-by: Krzysztof Wilczyński Reviewed-by: Logan Gunthorpe --- drivers/pci/p2pdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 8d47cb7218d1..081c391690d4 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -710,7 +710,7 @@ void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size) if (!ret) goto out; - if (unlikely(!percpu_ref_tryget_live(ref))) { + if (unlikely(!percpu_ref_tryget_live_rcu(ref))) { gen_pool_free(p2pdma->pool, (unsigned long) ret, size); ret = NULL; goto out;