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From: Warner Losh <imp@bsdimp.com>
To: qemu-devel@nongnu.org
Cc: kevans@freebsd.org, Guy Yur <guyyur@gmail.com>,
	richard.henderson@linaro.org, f4bug@amsat.org,
	Warner Losh <imp@bsdimp.com>
Subject: [PATCH v2 7/9] bsd-user/mmap.c: Don't mmap fd == -1 independently from MAP_ANON flag
Date: Tue, 21 Sep 2021 22:56:34 -0600	[thread overview]
Message-ID: <20210922045636.25206-8-imp@bsdimp.com> (raw)
In-Reply-To: <20210922045636.25206-1-imp@bsdimp.com>

From: Guy Yur <guyyur@gmail.com>

Switch checks for !(flags & MAP_ANONYMOUS) with checks for fd != -1.
MAP_STACK and MAP_GUARD both require fd == -1 and don't require mapping
the fd either.

Signed-off-by: Guy Yur <guyyur@gmail.com>
[ partially merged before, finishing the job and documenting origin]
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/mmap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 8b763fffc3..347d314aa9 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -154,7 +154,7 @@ static int mmap_frag(abi_ulong real_start,
     if (prot1 == 0) {
         /* no page was there, so we allocate one */
         void *p = mmap(host_start, qemu_host_page_size, prot,
-                       flags | MAP_ANON, -1, 0);
+                       flags | ((fd != -1) ? MAP_ANON : 0), -1, 0);
         if (p == MAP_FAILED)
             return -1;
         prot1 = prot;
@@ -162,7 +162,7 @@ static int mmap_frag(abi_ulong real_start,
     prot1 &= PAGE_BITS;
 
     prot_new = prot | prot1;
-    if (!(flags & MAP_ANON)) {
+    if (fd != -1) {
         /* msync() won't work here, so we return an error if write is
            possible while it is a shared mapping */
         if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
@@ -571,7 +571,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
          * worst case: we cannot map the file because the offset is not
          * aligned, so we read it
          */
-        if (!(flags & MAP_ANON) &&
+        if (fd != -1 &&
             (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
             /*
              * msync() won't work here, so we return an error if write is
-- 
2.32.0



  parent reply	other threads:[~2021-09-22  5:05 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22  4:56 [PATCH v2 0/9] bsd-user mmap fixes Warner Losh
2021-09-22  4:56 ` [PATCH v2 1/9] bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag() Warner Losh
2021-09-23 17:35   ` Richard Henderson
2021-09-22  4:56 ` [PATCH v2 2/9] bsd-user/mmap.c: check pread's return value to fix warnings with _FORTIFY_SOURCE Warner Losh
2021-09-23 17:36   ` Richard Henderson
2021-09-24 15:07     ` Warner Losh
2021-09-25 10:54   ` Philippe Mathieu-Daudé
2021-09-22  4:56 ` [PATCH v2 3/9] bsd-user/mmap.c: MAP_ symbols are defined, so no need for ifdefs Warner Losh
2021-09-23 17:37   ` Richard Henderson
2021-09-22  4:56 ` [PATCH v2 4/9] bsd-user/mmap.c: mmap return ENOMEM on overflow Warner Losh
2021-09-23 17:38   ` Richard Henderson
2021-09-25 10:55   ` Philippe Mathieu-Daudé
2021-09-22  4:56 ` [PATCH v2 5/9] bsd-user/mmap.c: mmap prefer MAP_ANON for BSD Warner Losh
2021-09-23 17:38   ` Richard Henderson
2021-09-22  4:56 ` [PATCH v2 6/9] bsd-user/mmap.c: line wrap change Warner Losh
2021-09-23 17:41   ` Richard Henderson
2021-09-26 16:46     ` Warner Losh
2021-09-22  4:56 ` Warner Losh [this message]
2021-09-23 17:43   ` [PATCH v2 7/9] bsd-user/mmap.c: Don't mmap fd == -1 independently from MAP_ANON flag Richard Henderson
2021-09-26 17:08     ` Warner Losh
2021-09-26 19:07       ` Guy Yur
2021-09-27  0:17         ` Warner Losh
2021-09-22  4:56 ` [PATCH v2 8/9] bsd-user/mmap.c: Implement MAP_EXCL, required by jemalloc in head Warner Losh
2021-09-23 17:52   ` Richard Henderson
2021-09-26 18:38     ` Warner Losh
2021-09-22  4:56 ` [PATCH v2 9/9] bsd-user/mmap.c: assert that target_mprotect cannot fail Warner Losh
2021-09-23 17:53   ` Richard Henderson
2021-09-25 10:58   ` Philippe Mathieu-Daudé

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