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charset="UTF-8" X-Rspamd-Queue-Id: 84D5D140015 X-Stat-Signature: kp7apdhqcjh5mjiqbg91yryoi3epydjj X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1674684920-784336 X-HE-Meta: U2FsdGVkX1/SDhDhT3KRICfgnslpR42A+9A+ni+PnVa6nZASjdZuoEgx3VgJVhJieMH8gABzHSYbTsw0ouwoNGmuO4/sr32KpQAoE6wlsTg1fUKV/Tllksnmjoaak9KEi+6EFcuT03/IJbgxaHKnLeLlfw6i+Li2equjA51Vqxw7i8KhxPS1bfDIXz5Y03h78BVZs4mt0M9dSEWvo0Q4W8ql9KfYcQTA/EHUukiVAijP47rzKisuSiAUcbIulzsQ/pKOuVTeZ6nr0/eqitI+ybWLbrV/e3OIzJcObGqeZd+MBt45wF2Z+uQ24t9TezP0OTjNM4c08nJjyXwmvcmBuc+5ElnA/jLEVhDtWH0AQXSeSEO1RGo8VdRWT2oooB+x81Xfa+VOPxOv9akuPLJBzBFQawIjObxQNQ3jNNyKvtByxiZhGCftbj1JEJGXMfSKMss7FvLZv1C6sFXeIu+r/B89GpAgRcXjg+y167O8rk5YlTjWf8NNHbYEukordlrzHK1qb8an19mrQflPVpMTs6rifRmhUSGjnLPID/fTLmh7RQ1iU3+D/GXiCg3LI7KjBBhf/FPE75O3xEbhcjatbXh6pLYiPqh/Lde6KvFXKeC172oSRdpch70U/56uvi7euds5J8JeMgxFYTkI1JKHTPi77SZQb4k+GsluCM5K3ORW5GbaXEM+p7R6XQ8NoEOBn8O6g0kLYa8OlOOcvBqrGnl7DZYsIfhD63eocA4Yz9uDXuCgLmYsHaa9RXKmnAGjufBwdjIq65trmXowACoF/6jTuGTwXFipZGXqi71LOWi6KK2UDVbHtxwkZ7ztZJMhn9XgWO7oZt6N3vQr9hiWcYyjkxB+OBGz8EMAODSCF7mweyc11RLwtDJGuFJjGPTWhCmoXign66tY+ziq+x80uII96PdKPsZnhSlwX9VfxN1i/vLXtuDUiquc+BDm/CuVFL6hHRL4TnWp0j09bbo 4Mxf/B0a isfCmDbunDDHAg9u5sRfAQqzD0tC0XVZETAa0p6t91Vhic1u4NXMJYn6PYDaxkDqi4pERj5YZIHcXb3RmUcS43Hz4bak0YEnCds1LzqB//xMMB2zlnwSgN+UoBgrf/UaOPyQlweBc/rDmtaaxKFzWmxSCxzgYIH5oz87vMuP1wjJe4gw+Jh4Us9LdzI815OFxJ/GGhLHLRPjOl8eHtVkjFqXtUtFCJSEcvkJ/4XJcWzXvYUeqTYTR4i0KysjCkbQI+OXOCcHsrSsdRAWse8gGfJ9ewj8v9cShiwKjqj8wr2J2uN2OMlNk1RwiOp7Zt0aDZshK3SUWAsliFNVxjDPsd/gGJ30oL4mb2Q2M X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jan 25, 2023 at 12:35 PM Matthew Wilcox wrote: > > [I'm just going to trim the incredibly long list of recipients. Too > many bounces, and I doubt any of them really care] I noticed that. I'll post the v3 with the original list for per-vma locks, if there are no objections. All the people who commented so far were in that list. > > On Wed, Jan 25, 2023 at 11:21:56AM -0800, Suren Baghdasaryan wrote: > > On Wed, Jan 25, 2023 at 10:37 AM Matthew Wilcox wrote: > > > Here's a trick I saw somewhere in the VFS: > > > > > > union { > > > const vm_flags_t vm_flags; > > > vm_flags_t __private __vm_flags; > > > }; > > > > > > Now it can be read by anybody but written only by those using > > > ACCESS_PRIVATE. > > > > Huh, this is quite nice! I think it does not save us from the cases > > when vma->vm_flags is passed by a reference and modified indirectly, > > like in ksm_madvise()? Though maybe such usecases are so rare (I found > > only 2 cases) that we can ignore this? > > Taking the address of vma->vm_flags will give you a const-qualified > pointer, which gcc will then warn about passing to a non-const-qualified > function argument, so I think we're good? >