diff --git a/sys/geom/zero/g_zero.c b/sys/geom/zero/g_zero.c index be31cc794cb5..6af29ca117ab 100644 --- a/sys/geom/zero/g_zero.c +++ b/sys/geom/zero/g_zero.c @@ -1,145 +1,189 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2005 Pawel Jakub Dawidek * All rights reserved. + * Copyright (c) 2025 Mateusz Piotrowski <0mp@FreeBSD.org> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include +#include +#include #include #define G_ZERO_CLASS_NAME "ZERO" -static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS); +static int g_zero_byte_sysctl(SYSCTL_HANDLER_ARGS); SYSCTL_DECL(_kern_geom); static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "GEOM_ZERO stuff"); static int g_zero_clear = 1; -SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, - CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, &g_zero_clear, 0, - g_zero_clear_sysctl, "I", +SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, + CTLFLAG_RWTUN, &g_zero_clear, 0, "Clear read data buffer"); static int g_zero_byte = 0; -SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RWTUN, &g_zero_byte, 0, +static uint8_t g_zero_buffer[PAGE_SIZE]; +SYSCTL_PROC(_kern_geom_zero, OID_AUTO, byte, + CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, &g_zero_byte, 0, + g_zero_byte_sysctl, "I", "Byte (octet) value to clear the buffers with"); static struct g_provider *gpp; static int -g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) +g_zero_byte_sysctl(SYSCTL_HANDLER_ARGS) { int error; - error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); + // XXX: Confirm that this is called on module load as well. + // XXX: Shouldn't we lock here to avoid changing the byte value if the + // driver is in the process of handling I/O? + error = sysctl_handle_int(oidp, &g_zero_byte, 0, req); if (error != 0 || req->newptr == NULL) return (error); - if (gpp == NULL) - return (ENXIO); - if (g_zero_clear) - gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; - else - gpp->flags |= G_PF_ACCEPT_UNMAPPED; + memset(g_zero_buffer, g_zero_byte, PAGE_SIZE); return (0); } +static void +g_zero_fill_pages(struct bio *bp) +{ + struct iovec aiovec; + struct uio auio; + size_t length; + vm_offset_t offset; + + aiovec.iov_base = g_zero_buffer; + aiovec.iov_len = PAGE_SIZE; + auio.uio_iov = &aiovec; + auio.uio_iovcnt = 1; + auio.uio_offset = 0; + auio.uio_segflg = UIO_SYSSPACE; + auio.uio_rw = UIO_WRITE; + auio.uio_td = curthread; + + /* + * To handle the unmapped I/O request, we need to fill the pages in the + * bp->bio_ma array with the g_zero_byte value. However, instead of + * setting every byte individually, we use uiomove_fromphys() to fill a + * page at a time with g_zero_buffer. + */ + bp->bio_resid = bp->bio_length; + offset = bp->bio_ma_offset & PAGE_MASK; + for (int i = 0; i < bp->bio_ma_n && bp->bio_resid > 0; i++) { + length = MIN(PAGE_SIZE - offset, bp->bio_resid); + auio.uio_resid = length; + + (void)uiomove_fromphys(&bp->bio_ma[i], offset, length, &auio); + + offset = 0; + bp->bio_resid -= length; + } +} + + static void g_zero_start(struct bio *bp) { - int error = ENXIO; + int error; switch (bp->bio_cmd) { case BIO_READ: - if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) - memset(bp->bio_data, g_zero_byte, bp->bio_length); + if (g_zero_clear) { + if ((bp->bio_flags & BIO_UNMAPPED) != 0) + g_zero_fill_pages(bp); + else + memset(bp->bio_data, g_zero_byte, + bp->bio_length); + } /* FALLTHROUGH */ case BIO_DELETE: case BIO_WRITE: bp->bio_completed = bp->bio_length; error = 0; break; case BIO_GETATTR: default: error = EOPNOTSUPP; break; } g_io_deliver(bp, error); } static void g_zero_init(struct g_class *mp) { struct g_geom *gp; struct g_provider *pp; g_topology_assert(); gp = g_new_geomf(mp, "gzero"); gp->start = g_zero_start; gp->access = g_std_access; gpp = pp = g_new_providerf(gp, "%s", gp->name); - pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; - if (!g_zero_clear) - pp->flags |= G_PF_ACCEPT_UNMAPPED; + pp->flags |= G_PF_ACCEPT_UNMAPPED | G_PF_DIRECT_SEND | + G_PF_DIRECT_RECEIVE; pp->mediasize = 1152921504606846976LLU; pp->sectorsize = 512; g_error_provider(pp, 0); } static int g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, struct g_geom *gp) { struct g_provider *pp; g_topology_assert(); if (gp == NULL) return (0); pp = LIST_FIRST(&gp->provider); if (pp == NULL) return (0); if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) return (EBUSY); gpp = NULL; g_wither_geom(gp, ENXIO); return (0); } static struct g_class g_zero_class = { .name = G_ZERO_CLASS_NAME, .version = G_VERSION, .init = g_zero_init, .destroy_geom = g_zero_destroy_geom }; DECLARE_GEOM_CLASS(g_zero_class, g_zero); MODULE_VERSION(geom_zero, 0);