Decouple filemem from platform and move it to pgalloc.MemoryFile.

This is in preparation for improved page cache reclaim, which requires
greater integration between the page cache and page allocator.

PiperOrigin-RevId: 238444706
Change-Id: Id24141b3678d96c7d7dc24baddd9be555bffafe4

2 files changed, 12 insertions, 11 deletions

diff --git a/pkg/sentry/loader/BUILD b/pkg/sentry/loader/BUILD
index 1ea260a4e..66300f25a 100644
--- a/pkg/sentry/loader/BUILD
+++ b/pkg/sentry/loader/BUILD
@@ -39,7 +39,7 @@ go_library(
         "//pkg/sentry/limits",
         "//pkg/sentry/memmap",
         "//pkg/sentry/mm",
-        "//pkg/sentry/platform",
+        "//pkg/sentry/pgalloc",
         "//pkg/sentry/safemem",
         "//pkg/sentry/uniqueid",
         "//pkg/sentry/usage",
diff --git a/pkg/sentry/loader/vdso.go b/pkg/sentry/loader/vdso.go
index c070c7316..273f6b5b9 100644
--- a/pkg/sentry/loader/vdso.go
+++ b/pkg/sentry/loader/vdso.go
@@ -28,7 +28,7 @@ import (
 	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/mm"
-	"gvisor.googlesource.com/gvisor/pkg/sentry/platform"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/pgalloc"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/safemem"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/uniqueid"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/usage"
@@ -217,7 +217,7 @@ type VDSO struct {
 
 // PrepareVDSO validates the system VDSO and returns a VDSO, containing the
 // param page for updating by the kernel.
-func PrepareVDSO(p platform.Platform) (*VDSO, error) {
+func PrepareVDSO(mfp pgalloc.MemoryFileProvider) (*VDSO, error) {
 	vdsoFile := newByteReaderFile(vdsoBin)
 
 	// First make sure the VDSO is valid. vdsoFile does not use ctx, so a
@@ -234,35 +234,36 @@ func PrepareVDSO(p platform.Platform) (*VDSO, error) {
 		return nil, fmt.Errorf("VDSO size overflows? %#x", len(vdsoBin))
 	}
 
-	vdso, err := p.Memory().Allocate(uint64(size), usage.System)
+	mf := mfp.MemoryFile()
+	vdso, err := mf.Allocate(uint64(size), usage.System)
 	if err != nil {
 		return nil, fmt.Errorf("unable to allocate VDSO memory: %v", err)
 	}
 
-	ims, err := p.Memory().MapInternal(vdso, usermem.ReadWrite)
+	ims, err := mf.MapInternal(vdso, usermem.ReadWrite)
 	if err != nil {
-		p.Memory().DecRef(vdso)
+		mf.DecRef(vdso)
 		return nil, fmt.Errorf("unable to map VDSO memory: %v", err)
 	}
 
 	_, err = safemem.CopySeq(ims, safemem.BlockSeqOf(safemem.BlockFromSafeSlice(vdsoBin)))
 	if err != nil {
-		p.Memory().DecRef(vdso)
+		mf.DecRef(vdso)
 		return nil, fmt.Errorf("unable to copy VDSO into memory: %v", err)
 	}
 
 	// Finally, allocate a param page for this VDSO.
-	paramPage, err := p.Memory().Allocate(usermem.PageSize, usage.System)
+	paramPage, err := mf.Allocate(usermem.PageSize, usage.System)
 	if err != nil {
-		p.Memory().DecRef(vdso)
+		mf.DecRef(vdso)
 		return nil, fmt.Errorf("unable to allocate VDSO param page: %v", err)
 	}
 
 	return &VDSO{
-		ParamPage: mm.NewSpecialMappable("[vvar]", p, paramPage),
+		ParamPage: mm.NewSpecialMappable("[vvar]", mfp, paramPage),
 		// TODO: Don't advertise the VDSO, as some applications may
 		// not be able to handle multiple [vdso] hints.
-		vdso:  mm.NewSpecialMappable("", p, vdso),
+		vdso:  mm.NewSpecialMappable("", mfp, vdso),
 		phdrs: info.phdrs,
 	}, nil
 }