On Thu, May 28, 2020 at 02:32:42AM +0530, Souptick Joarder wrote: > This code was using get_user_pages_fast(), in a "Case 2" scenario > (DMA/RDMA), using the categorization from [1]. That means that it's > time to convert the get_user_pages_fast() + put_page() calls to > pin_user_pages_fast() + unpin_user_page() calls. You are saying that the page is used for DIO and not DMA, but it sure looks to me like it is used for DMA. 503 /* Map the page into DMA space. */ 504 ptes[i].dma_addr = 505 dma_map_page(pg_tbl->device, page, 0, PAGE_SIZE, 506 DMA_BIDIRECTIONAL); To be honest, that starting paragraph was confusing. At first I thought you were saying gasket was an RDMA driver. :P I shouldn't have to read a different document to understand the commit message. It should be summarized enough and the other documentation is supplemental. "In 2019 we introduced pin_user_pages() and now we are converting get_user_pages() to the new API as appropriate". > > There is some helpful background in [2]: basically, this is a small > part of fixing a long-standing disconnect between pinning pages, and > file systems' use of those pages. What is the impact of this patch on runtime? > > [1] Documentation/core-api/pin_user_pages.rst > > [2] "Explicit pinning of user-space pages": > https://lwn.net/Articles/807108/ > > Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx> > Cc: John Hubbard <jhubbard@xxxxxxxxxx> > > Hi, > > I'm compile tested this, but unable to run-time test, so any testing > help is much appriciated. > --- The "Hi" part of patch should have been under the "---" cut off line so this will definitely need to be resent. regards, dan carpenter _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
